android/app/src/main/java/com/fabledsword/thoughtsync/MainActivity.kt

@@ -4,14 +4,17 @@ import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
+import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.lifecycle.viewmodel.compose.viewModel
+import com.fabledsword.thoughtsync.core.ThoughtSync
 import com.fabledsword.thoughtsync.ui.BoardScreen
 import com.fabledsword.thoughtsync.ui.BoardViewModel
 import com.fabledsword.thoughtsync.ui.ComposeSheet
+import com.fabledsword.thoughtsync.ui.NoteEditorScreen
 import com.fabledsword.thoughtsync.ui.StoreUnavailableScreen
 import com.fabledsword.thoughtsync.ui.ThoughtSyncTheme
 
@@ -31,31 +34,63 @@ class MainActivity : ComponentActivity() {
                     // than render an empty board that looks like data loss.
                     StoreUnavailableScreen(reason = app.openFailure)
                 } else {
-                    val model: BoardViewModel = viewModel(factory = BoardViewModel.factory(core))
-                    // Sheet visibility is view STATE, not view-model state: it is
-                    // about what is on screen, and nothing in the store cares.
-                    var composing by remember { mutableStateOf(false) }
-
-                    BoardScreen(
-                        state = model.state,
-                        onOpen = model::open,
-                        onSearch = model::search,
-                        onCompose = { composing = true },
-                        onDismissError = model::dismissError,
-                    )
-
-                    if (composing) {
-                        ComposeSheet(
-                            saving = model.state.saving,
-                            onDismiss = { composing = false },
-                            onSave = { kind, title, content ->
-                                model.create(kind, title, content)
-                                composing = false
-                            },
-                        )
-                    }
+                    App(core)
                 }
             }
         }
     }
 }
+
+/**
+ * The whole app, once the store is open.
+ *
+ * Board or editor, never both: the editor is a full screen, so composing the board
+ * behind it would keep a two-column grid measuring and recomposing under something
+ * that entirely covers it.
+ *
+ * No navigation library. There are exactly two destinations and the back gesture
+ * is handled by the editor itself — a nav graph here would be ceremony around a
+ * single nullable, and the editor's state already lives in the view model where a
+ * process death can restore it.
+ */
+@Composable
+private fun App(core: ThoughtSync) {
+    val model: BoardViewModel = viewModel(factory = BoardViewModel.factory(core))
+    // Sheet visibility is view STATE, not view-model state: it is about what is on
+    // screen, and nothing in the store cares.
+    var composing by remember { mutableStateOf(false) }
+
+    val editing = model.state.editing
+    if (editing != null) {
+        NoteEditorScreen(
+            note = editing,
+            labels = model.state.labels,
+            saving = model.state.saving,
+            error = model.state.error,
+            // The one seam between the editor and the store. Exhaustive at the
+            // other end, so a new action cannot be added without being handled.
+            onAction = { model.onEditorAction(editing, it) },
+        )
+        return
+    }
+
+    BoardScreen(
+        state = model.state,
+        onOpen = model::open,
+        onOpenNote = model::openNote,
+        onSearch = model::search,
+        onCompose = { composing = true },
+        onDismissError = model::dismissError,
+    )
+
+    if (composing) {
+        ComposeSheet(
+            saving = model.state.saving,
+            onDismiss = { composing = false },
+            onSave = { kind, title, content ->
+                model.create(kind, title, content)
+                composing = false
+            },
+        )
+    }
+}

android/app/src/main/java/com/fabledsword/thoughtsync/ui/BoardScreen.kt

@@ -1,8 +1,5 @@
 package com.fabledsword.thoughtsync.ui
 
-import androidx.compose.foundation.background
-import androidx.compose.foundation.border
-import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.PaddingValues
@@ -41,16 +38,11 @@ import androidx.compose.material3.NavigationDrawerItem
 import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
-import androidx.compose.material3.TextButton
-import androidx.compose.material3.TextField
-import androidx.compose.material3.TextFieldDefaults
 import androidx.compose.material3.rememberDrawerState
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
-import androidx.compose.ui.draw.clip
-import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.input.ImeAction
 import androidx.compose.ui.unit.dp
@@ -63,6 +55,7 @@ import kotlinx.coroutines.launch
 fun BoardScreen(
     state: BoardState,
     onOpen: (Destination) -> Unit,
+    onOpenNote: (Note) -> Unit,
     onSearch: (String) -> Unit,
     onCompose: () -> Unit,
     onDismissError: () -> Unit,
@@ -110,7 +103,7 @@ fun BoardScreen(
                 when {
                     state.loading -> LoadingBoard()
                     state.notes.isEmpty() -> EmptyBoard(state)
-                    else -> NoteBoard(notes = state.notes)
+                    else -> NoteBoard(notes = state.notes, onOpenNote = onOpenNote)
                 }
             }
         }
@@ -147,21 +140,17 @@ private fun SearchBar(
             IconButton(onClick = onMenu) {
                 Icon(Icons.Filled.Menu, contentDescription = stringResource(R.string.nav_open))
             }
-            TextField(
+            PlainTextField(
                 value = query,
                 onValueChange = onQueryChange,
                 modifier = Modifier.weight(1f),
-                placeholder = { Text(stringResource(R.string.search_hint)) },
+                hint = R.string.search_hint,
                 singleLine = true,
+                // The search key is decorative here: results already land as you
+                // type, so pressing it should dismiss the keyboard and change
+                // nothing, which is what an empty handler does.
                 keyboardOptions = KeyboardOptions(imeAction = ImeAction.Search),
                 keyboardActions = KeyboardActions(onSearch = {}),
-                colors =
-                    TextFieldDefaults.colors(
-                        focusedContainerColor = Color.Transparent,
-                        unfocusedContainerColor = Color.Transparent,
-                        focusedIndicatorColor = Color.Transparent,
-                        unfocusedIndicatorColor = Color.Transparent,
-                    ),
             )
             if (query.isNotEmpty()) {
                 IconButton(onClick = { onQueryChange("") }) {
@@ -241,7 +230,10 @@ private fun DrawerRow(
  * ones. This is the Compose equivalent of the CSS multi-column `NoteGrid.vue` uses.
  */
 @Composable
-private fun NoteBoard(notes: List<Note>) {
+private fun NoteBoard(
+    notes: List<Note>,
+    onOpenNote: (Note) -> Unit,
+) {
     LazyVerticalStaggeredGrid(
         columns = StaggeredGridCells.Fixed(BOARD_COLUMNS),
         modifier = Modifier.fillMaxSize(),
@@ -253,7 +245,9 @@ private fun NoteBoard(notes: List<Note>) {
         // Keyed by id so Compose reuses cards across a refresh rather than
         // rebuilding them — and so a newly captured note slides in instead of
         // making every card below it flicker.
-        items(items = notes, key = { it.id }) { note -> NoteCard(note) }
+        items(items = notes, key = { it.id }) { note ->
+            NoteCard(note = note, onOpen = { onOpenNote(note) })
+        }
     }
 }
 
@@ -307,33 +301,6 @@ private fun LoadingBoard() {
     }
 }
 
-@Composable
-private fun ErrorBanner(
-    message: String,
-    onDismiss: () -> Unit,
-) {
-    val dark = isSystemInDarkTheme()
-    val tint = noteTint("red")
-    Row(
-        modifier =
-            Modifier
-                .fillMaxWidth()
-                .padding(horizontal = GUTTER, vertical = 4.dp)
-                .clip(RoundedCornerShape(CARD_RADIUS))
-                .background(tint.background(dark))
-                .border(1.dp, tint.border(dark), RoundedCornerShape(CARD_RADIUS))
-                .padding(start = 12.dp),
-        verticalAlignment = Alignment.CenterVertically,
-    ) {
-        Text(
-            text = message,
-            style = MaterialTheme.typography.bodyMedium,
-            modifier = Modifier.weight(1f),
-        )
-        TextButton(onClick = onDismiss) { Text(stringResource(R.string.error_dismiss)) }
-    }
-}
-
 /**
  * Shown when the store could not be opened at all.
  *
@@ -362,5 +329,4 @@ fun StoreUnavailableScreen(reason: String?) {
 
 private const val BOARD_COLUMNS = 2
 private val GUTTER = 12.dp
-private val CARD_RADIUS = 12.dp
 private val SEARCH_RADIUS = 28.dp

android/app/src/main/java/com/fabledsword/thoughtsync/ui/BoardViewModel.kt

@@ -9,6 +9,7 @@ import androidx.lifecycle.viewModelScope
 import com.fabledsword.thoughtsync.core.Label
 import com.fabledsword.thoughtsync.core.Note
 import com.fabledsword.thoughtsync.core.NoteDraft
+import com.fabledsword.thoughtsync.core.NoteEdit
 import com.fabledsword.thoughtsync.core.NoteQuery
 import com.fabledsword.thoughtsync.core.ThoughtSync
 import kotlinx.coroutines.Dispatchers
@@ -61,6 +62,15 @@ data class BoardState(
     val loading: Boolean = true,
     val saving: Boolean = false,
     val error: String? = null,
+    /**
+     * The note the editor is open on, or null for the board.
+     *
+     * The NOTE and not its id, so the editor always renders from the same object
+     * the store last returned. Every mutation hands back the reloaded note, so
+     * ticking a box or picking a colour updates this in place and the editor never
+     * has to re-query to see its own change.
+     */
+    val editing: Note? = null,
 ) {
     /** Search overrides the destination while there is a query to run. */
     val searching: Boolean get() = query.isNotBlank()
@@ -72,7 +82,15 @@ data class BoardState(
  * Every store call is a BLOCKING FFI call — synchronous SQLite behind a mutex — so
  * they run on [Dispatchers.IO]. Doing otherwise would block the main thread on
  * disk, which is the jank a native client exists to avoid.
+ *
+ * ONE view model for both screens, over detekt's objection. The obvious split —
+ * a second one for the editor — fails on the fact that every editor mutation has
+ * to reload the board behind it, so the editor's view model would need a
+ * reference back into this one and the two would share the note list anyway. What
+ * is left is a dozen small functions around a single coherent state machine,
+ * which is what the suppression says rather than hides.
  */
+@Suppress("TooManyFunctions")
 class BoardViewModel(
     private val core: ThoughtSync,
 ) : ViewModel() {
@@ -127,11 +145,6 @@ class BoardViewModel(
             is Destination.WithLabel -> core.listNotes(query(VIEW_NOTES, labelId = destination.id))
         }
 
-    private fun query(
-        view: String,
-        labelId: String? = null,
-    ) = NoteQuery(view = view, labelId = labelId, sort = null, facets = null)
-
     private fun loadLabels() {
         viewModelScope.launch {
             runCatching { withContext(Dispatchers.IO) { core.listLabels() } }
@@ -206,37 +219,187 @@ class BoardViewModel(
         }
     }
 
-    private fun draft(
-        kind: DraftKind,
-        title: String,
-        content: String,
-    ): NoteDraft =
-        when (kind) {
-            // Body left to carry the text; the core derives display_title from its
-            // first line when no title was given, so a captured thought is nameable
-            // without making the user name it.
-            DraftKind.NOTE ->
-                NoteDraft(title = title, body = content, color = DEFAULT_COLOR, kind = null, items = null)
-            // One line per item. Fast to type on a phone and unambiguous, versus a
-            // row-by-row editor that costs a tap per entry.
-            DraftKind.LIST ->
-                NoteDraft(
-                    title = title,
-                    body = "",
-                    color = DEFAULT_COLOR,
-                    kind = KIND_LIST,
-                    items = content.lines().map { it.trim() }.filter { it.isNotEmpty() },
+    // ───────────────────────────────  the editor  ──────────────────────────────
+
+    fun openNote(note: Note) {
+        state = state.copy(editing = note)
+    }
+
+    /**
+     * Apply one editor action to the note the editor is open on.
+     *
+     * The `when` is exhaustive by construction, so adding a variant to
+     * [EditorAction] breaks THIS function until it is handled — which is the whole
+     * reason the editor speaks in actions rather than through a bundle of
+     * callbacks. The note is passed in rather than read from `state.editing` so a
+     * mutation that lands between a tap and its dispatch cannot redirect the
+     * action at a different note.
+     *
+     * Both suppressions have ONE cause: [EditorAction] has twenty variants, so a
+     * total function over it is twenty branches and sixty-odd lines no matter how
+     * it is written. Splitting it into sub-dispatchers is the only way to shorten
+     * it, and each of those would need an `else` — which throws away precisely the
+     * exhaustiveness this shape exists for. Suppressed rather than worked around,
+     * because the rules are measuring the action type's size, not this function's.
+     */
+    @Suppress("CyclomaticComplexMethod", "LongMethod")
+    fun onEditorAction(
+        note: Note,
+        action: EditorAction,
+    ) {
+        val id = note.id
+        when (action) {
+            EditorAction.Close -> state = state.copy(editing = null)
+            EditorAction.DismissError -> dismissError()
+
+            // Text is the only edit that batches: title and body are typed
+            // together and saved together on close, so they cost one write and
+            // one revision snapshot rather than two of each.
+            is EditorAction.SaveText ->
+                mutate {
+                    it.updateNote(
+                        id,
+                        listOf(
+                            // An emptied title CLEARS the column rather than
+                            // storing "". The core derives `display_title` from
+                            // the first body line when the title is null, so the
+                            // difference is whether an untitled note is nameable
+                            // or blank — exactly what `ClearTitle` exists for.
+                            if (action.title.isBlank()) {
+                                NoteEdit.ClearTitle
+                            } else {
+                                NoteEdit.Title(action.title.trim())
+                            },
+                            NoteEdit.Body(action.body),
+                        ),
+                    )
+                }
+
+            is EditorAction.SetColor -> edit(id, NoteEdit.Color(action.color))
+
+            EditorAction.ToggleKind ->
+                edit(id, NoteEdit.Kind(if (note.kind == KIND_LIST) KIND_TEXT else KIND_LIST))
+
+            // Pinning re-sorts the board rather than emptying it, and on a phone
+            // you often pin while still reading — so unlike the three below, it
+            // deliberately leaves the editor open.
+            is EditorAction.SetPinned -> edit(id, NoteEdit.Pinned(action.pinned))
+
+            // Archiving, trashing and restoring all take the note out of the list
+            // you were looking at, so the editor closes behind them: staying open
+            // on a note that has visibly left the board reads as a bug.
+            is EditorAction.SetArchived ->
+                mutate(closeEditor = true) {
+                    it.updateNote(id, listOf(NoteEdit.Archived(action.archived)))
+                }
+            EditorAction.Trash -> mutate(closeEditor = true) { it.trashNote(id) }
+            EditorAction.Restore -> mutate(closeEditor = true) { it.restoreNote(id) }
+            EditorAction.DeleteForever ->
+                mutate(closeEditor = true) {
+                    it.deleteNoteForever(id)
+                    // Nothing to hand back — the row is gone. The board reload
+                    // inside `mutate` is what makes it disappear.
+                    null
+                }
+
+            is EditorAction.AddItem ->
+                action.text.trim().takeIf { it.isNotEmpty() }?.let { text ->
+                    mutate { it.addItem(id, text) }
+                }
+            is EditorAction.SetItemChecked ->
+                mutate { it.setItemChecked(id, action.itemId, action.checked) }
+            is EditorAction.SetItemText ->
+                mutate { it.setItemText(id, action.itemId, action.text) }
+            is EditorAction.DeleteItem -> mutate { it.deleteItem(id, action.itemId) }
+
+            is EditorAction.SetLabels -> mutate { it.setNoteLabels(id, action.labelIds) }
+
+            is EditorAction.CreateLabel ->
+                action.name.trim().takeIf { it.isNotEmpty() }?.let { name ->
+                    mutate {
+                        val label = it.createLabel(name)
+                        val manual = note.labels.filterNot { l -> l.viaTag }.map { l -> l.id }
+                        it.setNoteLabels(id, (manual + label.id).distinct())
+                    }
+                    // The drawer lists labels with their note counts, and both
+                    // just changed.
+                    loadLabels()
+                }
+
+            is EditorAction.SetReminder -> edit(id, NoteEdit.RemindAt(action.at))
+            EditorAction.ClearReminder -> edit(id, NoteEdit.ClearRemindAt)
+            EditorAction.CompleteReminder -> mutate { it.completeReminder(id) }
+            is EditorAction.SnoozeReminder -> mutate { it.snoozeReminder(id, action.minutes) }
+            is EditorAction.SetRecurrence ->
+                edit(
+                    id,
+                    action.rule?.let { NoteEdit.Recurrence(it) } ?: NoteEdit.ClearRecurrence,
                 )
         }
+    }
+
+    /** The common case: one field-level edit to one note. */
+    private fun edit(
+        id: String,
+        change: NoteEdit,
+    ) = mutate { it.updateNote(id, listOf(change)) }
+
+    /**
+     * The one path every store mutation takes.
+     *
+     * Each core mutation returns the reloaded note, which goes straight into
+     * [BoardState.editing] so an open editor shows its own change without a
+     * re-query. The BOARD list is then reloaded rather than patched in place:
+     * pinning re-sorts it, archiving removes the note from it, and adding a label
+     * can move it in or out of a label view — a splice would have to reimplement
+     * the core's ordering and membership rules in Kotlin to get any of that right.
+     * The reload is a local SQLite query, so it costs less than the code that would
+     * avoid it.
+     *
+     * Quiet, deliberately: no spinner, because the board is already on screen with
+     * correct-until-a-moment-ago content, and flashing it empty would be a worse
+     * lie than showing it one frame stale.
+     *
+     * Search results are left alone — they are the answer to a query, not a live
+     * view, and re-running the board query underneath them would replace the hits
+     * with the whole board.
+     */
+    private fun mutate(
+        closeEditor: Boolean = false,
+        block: (ThoughtSync) -> Note?,
+    ) {
+        viewModelScope.launch {
+            state = state.copy(saving = true)
+            state =
+                try {
+                    val updated = withContext(Dispatchers.IO) { block(core) }
+                    val notes =
+                        if (state.searching) {
+                            state.notes
+                        } else {
+                            withContext(Dispatchers.IO) { load(state.destination) }
+                        }
+                    state.copy(
+                        notes = notes,
+                        editing = if (closeEditor) null else updated ?: state.editing,
+                        saving = false,
+                        error = null,
+                    )
+                } catch (e: Exception) {
+                    // Broad by intent, as elsewhere: the core reports every failure
+                    // as one error type carrying a message meant to be shown, and a
+                    // half-applied edit must still leave a usable screen.
+                    state.copy(saving = false, error = e.message ?: FALLBACK_ERROR)
+                }
+        }
+    }
 
     fun dismissError() {
         state = state.copy(error = null)
     }
 
     companion object {
-        private const val DEFAULT_COLOR = "default"
         private const val FALLBACK_ERROR = "Something went wrong."
-        private const val KIND_LIST = "list"
         private const val SEARCH_DEBOUNCE_MS = 180L
 
         // The core's board vocabulary. "archived", not "archive" — it matches on
@@ -252,3 +415,41 @@ class BoardViewModel(
             }
     }
 }
+
+/** The palette key a note starts on, matching the web and the desktop. */
+private const val DEFAULT_COLOR = "default"
+
+// ── pure builders ───────────────────────────────────────────────────────────
+//
+// Neither of these reads or writes view-model state; they only shape a core input
+// from arguments. Kept at file scope so the class above holds only things that
+// actually depend on it — which is also what keeps its function count meaningful.
+
+private fun query(
+    view: String,
+    labelId: String? = null,
+) = NoteQuery(view = view, labelId = labelId, sort = null, facets = null)
+
+private fun draft(
+    kind: DraftKind,
+    title: String,
+    content: String,
+): NoteDraft =
+    when (kind) {
+        // Body left to carry the text; the core derives display_title from its
+        // first line when no title was given, so a captured thought is nameable
+        // without making the user name it.
+        DraftKind.NOTE ->
+            NoteDraft(title = title, body = content, color = DEFAULT_COLOR, kind = null, items = null)
+        // One line per item. At CAPTURE time the whole list is already in your
+        // head, so typing it in one go beats a tap between each row; the editor
+        // has the per-row control for when the list is being revised instead.
+        DraftKind.LIST ->
+            NoteDraft(
+                title = title,
+                body = "",
+                color = DEFAULT_COLOR,
+                kind = KIND_LIST,
+                items = content.lines().map { it.trim() }.filter { it.isNotEmpty() },
+            )
+    }

android/app/src/main/java/com/fabledsword/thoughtsync/ui/ComposeSheet.kt

@@ -1,6 +1,5 @@
 package com.fabledsword.thoughtsync.ui
 
-import androidx.annotation.StringRes
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
@@ -14,8 +13,6 @@ import androidx.compose.material3.FilterChip
 import androidx.compose.material3.ModalBottomSheet
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
-import androidx.compose.material3.TextField
-import androidx.compose.material3.TextFieldDefaults
 import androidx.compose.material3.rememberModalBottomSheetState
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
@@ -26,7 +23,6 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.focus.FocusRequester
 import androidx.compose.ui.focus.focusRequester
-import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.unit.dp
 import com.fabledsword.thoughtsync.R
@@ -83,22 +79,23 @@ fun ComposeSheet(
                 )
             }
 
-            SheetField(
+            PlainTextField(
                 value = title,
                 onValueChange = { title = it },
                 hint = R.string.compose_title_hint,
+                singleLine = true,
             )
 
-            SheetField(
+            PlainTextField(
                 value = content,
                 onValueChange = { content = it },
+                modifier = Modifier.focusRequester(contentFocus),
                 hint =
                     if (kind == DraftKind.LIST) {
                         R.string.compose_list_hint
                     } else {
                         R.string.compose_body_hint
                     },
-                modifier = Modifier.focusRequester(contentFocus),
                 minLines = MIN_CONTENT_LINES,
             )
 
@@ -128,45 +125,4 @@ private fun SheetActions(
     }
 }
 
-/**
- * An undecorated field.
- *
- * The sheet is already a surface with its own edges; a filled field inside it
- * draws a second box around the same content and makes a quick note feel like a
- * form to fill in.
- */
-@OptIn(ExperimentalMaterial3Api::class)
-@Composable
-private fun SheetField(
-    value: String,
-    onValueChange: (String) -> Unit,
-    @StringRes hint: Int,
-    modifier: Modifier = Modifier,
-    minLines: Int = 1,
-) {
-    TextField(
-        value = value,
-        onValueChange = onValueChange,
-        modifier = modifier.fillMaxWidth(),
-        placeholder = { Text(stringResource(hint)) },
-        // A one-line field is a single-line field; keeping both as separate knobs
-        // only invited call sites that set them to disagree.
-        singleLine = minLines == 1,
-        minLines = minLines,
-        colors = transparentFieldColors(),
-    )
-}
-
-@OptIn(ExperimentalMaterial3Api::class)
-@Composable
-private fun transparentFieldColors() =
-    TextFieldDefaults.colors(
-        focusedContainerColor = Color.Transparent,
-        unfocusedContainerColor = Color.Transparent,
-        disabledContainerColor = Color.Transparent,
-        focusedIndicatorColor = Color.Transparent,
-        unfocusedIndicatorColor = Color.Transparent,
-        disabledIndicatorColor = Color.Transparent,
-    )
-
 private const val MIN_CONTENT_LINES = 4

android/app/src/main/java/com/fabledsword/thoughtsync/ui/EditorAction.kt

@@ -0,0 +1,121 @@
+package com.fabledsword.thoughtsync.ui
+
+/**
+ * Everything the editor can ask for, as one type.
+ *
+ * The alternative was a bundle of twenty callbacks, and it was a bad one: twenty
+ * same-shaped `(String, String) -> Unit` parameters is a place for two of them to
+ * get swapped, with nothing to catch it. One `(EditorAction) -> Unit` costs a
+ * `when` at the far end and gets EXHAUSTIVENESS in exchange — adding a variant
+ * here breaks the dispatcher until it is handled, which is precisely the guarantee
+ * the callback bundle could not offer.
+ *
+ * No variant carries a note id. The editor is open on exactly one note and the
+ * dispatcher already has it, so threading it through every action would only
+ * create the possibility of the two disagreeing.
+ */
+sealed interface EditorAction {
+    /** Leave the editor. Text is saved separately, via [SaveText], before this. */
+    data object Close : EditorAction
+
+    /** Clear the error banner. Shared state — the board shows the same one. */
+    data object DismissError : EditorAction
+
+    data class SaveText(
+        val title: String,
+        val body: String,
+    ) : EditorAction
+
+    data class SetColor(
+        val color: String,
+    ) : EditorAction
+
+    /**
+     * Note ⇄ checklist.
+     *
+     * Only `kind` changes: the body text and any existing items both stay where
+     * they are, so switching back and forth is lossless and a mis-tap costs
+     * nothing.
+     */
+    data object ToggleKind : EditorAction
+
+    data class SetPinned(
+        val pinned: Boolean,
+    ) : EditorAction
+
+    data class SetArchived(
+        val archived: Boolean,
+    ) : EditorAction
+
+    data object Trash : EditorAction
+
+    data object Restore : EditorAction
+
+    data object DeleteForever : EditorAction
+
+    data class AddItem(
+        val text: String,
+    ) : EditorAction
+
+    data class SetItemChecked(
+        val itemId: String,
+        val checked: Boolean,
+    ) : EditorAction
+
+    data class SetItemText(
+        val itemId: String,
+        val text: String,
+    ) : EditorAction
+
+    data class DeleteItem(
+        val itemId: String,
+    ) : EditorAction
+
+    /**
+     * The note's MANUAL labels, replacing whatever was there.
+     *
+     * `#tag` labels must never appear in this list. They are owned by the body
+     * text and the core re-derives them on every body edit — see
+     * `set_note_labels` in the FFI crate.
+     */
+    data class SetLabels(
+        val labelIds: List<String>,
+    ) : EditorAction
+
+    /**
+     * Create a label and attach it to this note in one gesture.
+     *
+     * Typing a new label in the picker and then having to tick it as well would
+     * be two steps for one intention. The core finds-or-creates, so typing the
+     * name of a label that already exists simply attaches that one.
+     */
+    data class CreateLabel(
+        val name: String,
+    ) : EditorAction
+
+    /** `at` is an RFC3339 instant — see `Time.kt` for why the UI writes it. */
+    data class SetReminder(
+        val at: String,
+    ) : EditorAction
+
+    data object ClearReminder : EditorAction
+
+    /**
+     * Mark the reminder dealt with.
+     *
+     * Distinct from [ClearReminder] even though the core does the same thing to
+     * the column today: this is where recurrence advancement lands when it is
+     * built, so a recurring reminder finished through the generic clear would
+     * silently stop recurring.
+     */
+    data object CompleteReminder : EditorAction
+
+    data class SnoozeReminder(
+        val minutes: Long,
+    ) : EditorAction
+
+    /** null is "does not repeat". */
+    data class SetRecurrence(
+        val rule: String?,
+    ) : EditorAction
+}

android/app/src/main/java/com/fabledsword/thoughtsync/ui/EditorChecklist.kt

@@ -0,0 +1,144 @@
+package com.fabledsword.thoughtsync.ui
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.text.KeyboardActions
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Add
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material3.Checkbox
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.focus.onFocusChanged
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.input.ImeAction
+import androidx.compose.ui.text.style.TextDecoration
+import androidx.compose.ui.unit.dp
+import com.fabledsword.thoughtsync.R
+import com.fabledsword.thoughtsync.core.ChecklistItem
+import com.fabledsword.thoughtsync.core.Note
+
+/**
+ * The checklist, with real checkboxes this time.
+ *
+ * The card renders glyphs because it is a preview; here every row is live. This is
+ * the other half of the answer to how a list gets typed on a phone: the capture
+ * sheet takes a whole list at once, one item per line, because at capture time the
+ * list is already in your head and a tap per row would be the slow part. The
+ * editor is where a list is REVISED, and revising is item-at-a-time — so this is
+ * where the per-row control lives.
+ *
+ * No empty state: a checklist with no items already shows the add row with its
+ * hint, which says the same thing an empty state would and can be typed into.
+ */
+@Composable
+fun ChecklistEditor(
+    note: Note,
+    readOnly: Boolean,
+    onAction: (EditorAction) -> Unit,
+) {
+    Column {
+        note.items.forEach { item ->
+            ChecklistRow(item = item, readOnly = readOnly, onAction = onAction)
+        }
+        if (!readOnly) {
+            AddItemRow(onAdd = { onAction(EditorAction.AddItem(it)) })
+        }
+    }
+}
+
+/**
+ * One row: a live checkbox, editable text, and a remove button.
+ *
+ * The text commits on FOCUS LOSS rather than per keystroke. Every commit is a
+ * store write that reloads the note, so per-keystroke saving would both hammer
+ * SQLite and race the reload against the next character.
+ */
+@Composable
+private fun ChecklistRow(
+    item: ChecklistItem,
+    readOnly: Boolean,
+    onAction: (EditorAction) -> Unit,
+) {
+    // Keyed by item id, so a reload after some OTHER row's edit doesn't reset the
+    // text being typed here.
+    var text by remember(item.id) { mutableStateOf(item.text) }
+    val commit = { if (text != item.text) onAction(EditorAction.SetItemText(item.id, text)) }
+
+    Row(verticalAlignment = Alignment.CenterVertically) {
+        Checkbox(
+            checked = item.checked,
+            onCheckedChange = { onAction(EditorAction.SetItemChecked(item.id, it)) },
+            enabled = !readOnly,
+        )
+        PlainTextField(
+            value = text,
+            onValueChange = { text = it },
+            modifier =
+                Modifier
+                    .weight(1f)
+                    .onFocusChanged { if (!it.isFocused) commit() },
+            enabled = !readOnly,
+            singleLine = true,
+            textStyle =
+                MaterialTheme.typography.bodyLarge.copy(
+                    // Struck through when done, matching the card and the web.
+                    textDecoration = if (item.checked) TextDecoration.LineThrough else null,
+                ),
+            keyboardOptions = KeyboardOptions(imeAction = ImeAction.Done),
+            keyboardActions = KeyboardActions(onDone = { commit() }),
+        )
+        if (!readOnly) {
+            IconButton(onClick = { onAction(EditorAction.DeleteItem(item.id)) }) {
+                Icon(
+                    Icons.Filled.Close,
+                    contentDescription = stringResource(R.string.editor_remove_item),
+                )
+            }
+        }
+    }
+}
+
+/**
+ * The always-present row at the bottom for adding an item.
+ *
+ * It clears but keeps focus after a submit, so a list can be typed straight
+ * through — "milk ⏎ eggs ⏎ bread" — rather than costing a tap between each. That
+ * is the same speed the capture sheet's one-item-per-line field buys, carried into
+ * the editor so refining a list never feels slower than making one.
+ */
+@Composable
+private fun AddItemRow(onAdd: (String) -> Unit) {
+    var text by remember { mutableStateOf("") }
+    Row(verticalAlignment = Alignment.CenterVertically) {
+        Icon(
+            Icons.Filled.Add,
+            contentDescription = null,
+            modifier = Modifier.padding(horizontal = 12.dp),
+            tint = MaterialTheme.colorScheme.onSurfaceVariant,
+        )
+        PlainTextField(
+            value = text,
+            onValueChange = { text = it },
+            modifier = Modifier.weight(1f),
+            hint = R.string.editor_add_item,
+            singleLine = true,
+            keyboardOptions = KeyboardOptions(imeAction = ImeAction.Done),
+            keyboardActions =
+                KeyboardActions(onDone = {
+                    onAdd(text)
+                    text = ""
+                }),
+        )
+    }
+}

android/app/src/main/java/com/fabledsword/thoughtsync/ui/EditorChrome.kt

@@ -0,0 +1,268 @@
+package com.fabledsword.thoughtsync.ui
+
+import androidx.annotation.StringRes
+import androidx.compose.foundation.background
+import androidx.compose.foundation.border
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.List
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material.icons.filled.Create
+import androidx.compose.material.icons.filled.MoreVert
+import androidx.compose.material.icons.filled.Notifications
+import androidx.compose.material3.BottomAppBar
+import androidx.compose.material3.DropdownMenu
+import androidx.compose.material3.DropdownMenuItem
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import com.fabledsword.thoughtsync.R
+import com.fabledsword.thoughtsync.core.Note
+
+/**
+ * The editor's action bar, at the bottom where a thumb already is.
+ *
+ * The three affordances with a permanent slot are the ones reached for while still
+ * writing — colour, reminder, note-or-list. Everything structural (pin, labels,
+ * archive, delete) is one tap further into the overflow, where it is spelled out
+ * in WORDS.
+ *
+ * That split is a deliberate trade against icon-guessing. `material-icons-core`
+ * carries no pin, archive or label glyph, and the two ways out were pulling in the
+ * ~1,000-vector extended set for four icons, or pressing unrelated ones into
+ * service — a star meaning "pin" is a star meaning "favourite" to everyone who has
+ * used another app. Text says exactly what it does and reads correctly aloud.
+ */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun EditorBottomBar(
+    note: Note,
+    readOnly: Boolean,
+    tint: NoteTint,
+    onPicker: (Picker) -> Unit,
+    onConfirmDelete: () -> Unit,
+    onAction: (EditorAction) -> Unit,
+) {
+    val dark = isSystemInDarkTheme()
+    BottomAppBar(containerColor = tint.background(dark)) {
+        if (!readOnly) {
+            // A dot in the note's CURRENT colour rather than a palette icon: it
+            // shows what the colour is as well as what the button does.
+            IconButton(onClick = { onPicker(Picker.COLOR) }) {
+                Box(
+                    modifier =
+                        Modifier
+                            .size(SWATCH_DOT)
+                            .clip(CircleShape)
+                            .background(tint.chipBackground(dark))
+                            .border(1.dp, tint.border(dark), CircleShape),
+                )
+            }
+            IconButton(onClick = { onPicker(Picker.REMINDER) }) {
+                Icon(
+                    Icons.Filled.Notifications,
+                    contentDescription = stringResource(R.string.editor_reminder),
+                )
+            }
+            IconButton(onClick = { onAction(EditorAction.ToggleKind) }) {
+                val list = note.kind == KIND_LIST
+                Icon(
+                    if (list) Icons.Filled.Create else Icons.AutoMirrored.Filled.List,
+                    contentDescription =
+                        stringResource(
+                            if (list) R.string.editor_make_note else R.string.editor_make_list,
+                        ),
+                )
+            }
+        }
+
+        Box(modifier = Modifier.weight(1f))
+
+        OverflowMenu(
+            note = note,
+            readOnly = readOnly,
+            onPicker = onPicker,
+            onConfirmDelete = onConfirmDelete,
+            onAction = onAction,
+        )
+    }
+}
+
+@Composable
+private fun OverflowMenu(
+    note: Note,
+    readOnly: Boolean,
+    onPicker: (Picker) -> Unit,
+    onConfirmDelete: () -> Unit,
+    onAction: (EditorAction) -> Unit,
+) {
+    var open by remember { mutableStateOf(false) }
+    val close = { open = false }
+    Box {
+        IconButton(onClick = { open = true }) {
+            Icon(Icons.Filled.MoreVert, contentDescription = stringResource(R.string.editor_more))
+        }
+        DropdownMenu(expanded = open, onDismissRequest = close) {
+            if (readOnly) {
+                MenuItem(R.string.editor_restore, close) { onAction(EditorAction.Restore) }
+                MenuItem(R.string.editor_delete_forever, close, onConfirmDelete)
+            } else {
+                MenuItem(
+                    if (note.pinned) R.string.editor_unpin else R.string.editor_pin,
+                    close,
+                ) { onAction(EditorAction.SetPinned(!note.pinned)) }
+                MenuItem(R.string.editor_labels, close) { onPicker(Picker.LABELS) }
+                MenuItem(
+                    if (note.archived) R.string.editor_unarchive else R.string.editor_archive,
+                    close,
+                ) { onAction(EditorAction.SetArchived(!note.archived)) }
+                MenuItem(R.string.editor_trash, close) { onAction(EditorAction.Trash) }
+            }
+        }
+    }
+}
+
+@Composable
+private fun MenuItem(
+    @StringRes labelRes: Int,
+    onClose: () -> Unit,
+    onClick: () -> Unit,
+) {
+    DropdownMenuItem(
+        text = { Text(stringResource(labelRes)) },
+        onClick = {
+            // Close BEFORE acting. An overflow menu left hanging over the sheet
+            // that just opened underneath it is the classic version of this bug,
+            // and doing it here means no call site can forget.
+            onClose()
+            onClick()
+        },
+    )
+}
+
+/**
+ * The note's labels, each removable.
+ *
+ * `#tag` labels get no remove button: they are owned by the body text and the core
+ * re-derives them on the next edit, so a cross that undid itself a second later
+ * would look broken. The way to remove one is to delete the tag from the text,
+ * which is what the trailing note says.
+ */
+@Composable
+fun EditorLabelRow(
+    note: Note,
+    readOnly: Boolean,
+    onAction: (EditorAction) -> Unit,
+) {
+    val dark = isSystemInDarkTheme()
+    Column(modifier = Modifier.padding(top = 12.dp)) {
+        note.labels.forEach { label ->
+            val tint = noteTint(label.color)
+            Row(
+                verticalAlignment = Alignment.CenterVertically,
+                modifier = Modifier.padding(vertical = 2.dp),
+            ) {
+                Text(
+                    text = label.name,
+                    style = MaterialTheme.typography.labelLarge,
+                    color = tint.chipForeground(dark),
+                    modifier =
+                        Modifier
+                            .clip(CircleShape)
+                            .background(tint.chipBackground(dark))
+                            .padding(horizontal = 10.dp, vertical = 4.dp),
+                )
+                if (label.viaTag) {
+                    Text(
+                        text = stringResource(R.string.label_from_tag),
+                        style = MaterialTheme.typography.labelSmall,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                        modifier = Modifier.padding(start = 8.dp),
+                    )
+                } else if (!readOnly) {
+                    IconButton(onClick = {
+                        // Only the MANUAL labels are sent: the core replaces
+                        // exactly those, and including a tag label here would ask
+                        // it to own something the body text already owns.
+                        val kept =
+                            note.labels
+                                .filterNot { it.viaTag || it.id == label.id }
+                                .map { it.id }
+                        onAction(EditorAction.SetLabels(kept))
+                    }) {
+                        Icon(
+                            Icons.Filled.Close,
+                            contentDescription = stringResource(R.string.editor_remove_label),
+                        )
+                    }
+                }
+            }
+        }
+    }
+}
+
+/**
+ * The set reminder, with the one-tap actions beside it.
+ *
+ * Done / 1h / 1d are the same three the web editor offers, for the same reason:
+ * when a reminder surfaces, the answer is almost always "handled" or "not yet",
+ * and making either of those cost a trip through the date picker is how a reminder
+ * ends up ignored instead of dealt with.
+ */
+@Composable
+fun EditorReminderRow(
+    at: String,
+    recurrence: String?,
+    readOnly: Boolean,
+    onAction: (EditorAction) -> Unit,
+) {
+    Column(modifier = Modifier.padding(top = 12.dp)) {
+        Text(
+            text = reminderLabel(at, recurrence),
+            style = MaterialTheme.typography.labelLarge,
+            color =
+                if (isPast(at)) {
+                    MaterialTheme.colorScheme.error
+                } else {
+                    MaterialTheme.colorScheme.onSurfaceVariant
+                },
+        )
+        if (!readOnly) {
+            Row(horizontalArrangement = Arrangement.spacedBy(4.dp)) {
+                TextButton(onClick = { onAction(EditorAction.CompleteReminder) }) {
+                    Text(stringResource(R.string.reminder_done))
+                }
+                TextButton(onClick = { onAction(EditorAction.SnoozeReminder(SNOOZE_HOUR)) }) {
+                    Text(stringResource(R.string.reminder_snooze_hour))
+                }
+                TextButton(onClick = { onAction(EditorAction.SnoozeReminder(SNOOZE_DAY)) }) {
+                    Text(stringResource(R.string.reminder_snooze_day))
+                }
+            }
+        }
+    }
+}
+
+private val SWATCH_DOT = 22.dp
+private const val SNOOZE_HOUR = 60L
+private const val SNOOZE_DAY = 1440L

android/app/src/main/java/com/fabledsword/thoughtsync/ui/EditorPickers.kt

@@ -0,0 +1,468 @@
+package com.fabledsword.thoughtsync.ui
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.border
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.heightIn
+import androidx.compose.foundation.layout.imePadding
+import androidx.compose.foundation.layout.navigationBarsPadding
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.text.KeyboardActions
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Check
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.Checkbox
+import androidx.compose.material3.DatePicker
+import androidx.compose.material3.DatePickerDialog
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.FilterChip
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.ModalBottomSheet
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.material3.TimePicker
+import androidx.compose.material3.rememberDatePickerState
+import androidx.compose.material3.rememberTimePickerState
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.input.ImeAction
+import androidx.compose.ui.unit.dp
+import com.fabledsword.thoughtsync.R
+import com.fabledsword.thoughtsync.core.Label
+import com.fabledsword.thoughtsync.core.Note
+import java.time.DayOfWeek
+import java.time.Instant
+import java.time.LocalDate
+import java.time.LocalDateTime
+import java.time.LocalTime
+import java.time.ZoneId
+import java.time.temporal.TemporalAdjusters
+
+// The three things you pick rather than type: a colour, a set of labels, a time.
+//
+// All bottom sheets rather than dialogs. A dialog takes the middle of the screen
+// and asks to be dismissed; a sheet rises from the bottom, under the thumb, with
+// the note still visible above it — which matters when the choice you are making
+// is about the thing you are looking at.
+
+/** The note palette, as swatches. Order and colours come from [NOTE_TINTS]. */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun ColorSheet(
+    selected: String,
+    onPick: (String) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    val dark = isSystemInDarkTheme()
+    ModalBottomSheet(onDismissRequest = onDismiss) {
+        Column(
+            modifier =
+                Modifier
+                    .fillMaxWidth()
+                    .padding(horizontal = 16.dp)
+                    .navigationBarsPadding(),
+        ) {
+            SheetTitle(R.string.color_picker_title)
+            // Chunked into fixed rows rather than a flow layout: ten swatches
+            // always lay out as two rows of five on every phone width, and a flow
+            // would reshuffle them between devices for no gain.
+            NOTE_TINTS.entries.chunked(SWATCHES_PER_ROW).forEach { row ->
+                Row(
+                    modifier = Modifier.fillMaxWidth().padding(vertical = 6.dp),
+                    horizontalArrangement = Arrangement.SpaceEvenly,
+                ) {
+                    row.forEach { (key, tint) ->
+                        Box(
+                            contentAlignment = Alignment.Center,
+                            modifier =
+                                Modifier
+                                    .size(SWATCH_SIZE)
+                                    .clip(CircleShape)
+                                    .background(tint.background(dark))
+                                    .border(
+                                        // The selected swatch gets a heavier ring
+                                        // as well as a tick: on the pale tints the
+                                        // tick alone is nearly invisible.
+                                        if (key == selected) 2.dp else 1.dp,
+                                        if (key == selected) {
+                                            MaterialTheme.colorScheme.primary
+                                        } else {
+                                            tint.border(dark)
+                                        },
+                                        CircleShape,
+                                    ).clickable(onClickLabel = tint.label) { onPick(key) },
+                        ) {
+                            if (key == selected) {
+                                Icon(
+                                    Icons.Filled.Check,
+                                    contentDescription = tint.label,
+                                    modifier = Modifier.size(18.dp),
+                                )
+                            }
+                        }
+                    }
+                    // Pad a short final row so its swatches line up with the row
+                    // above instead of spreading across the full width.
+                    repeat(SWATCHES_PER_ROW - row.size) {
+                        Box(modifier = Modifier.size(SWATCH_SIZE))
+                    }
+                }
+            }
+        }
+    }
+}
+
+/**
+ * Every label, ticked where it is on the note.
+ *
+ * `#tag` labels appear ticked and disabled — they are true of the note, and they
+ * are owned by its text, so showing them unticked would be a lie and letting them
+ * be unticked would be a control that undoes itself.
+ */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun LabelSheet(
+    note: Note,
+    labels: List<Label>,
+    onAction: (EditorAction) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    var typed by remember { mutableStateOf("") }
+    val manual =
+        note.labels
+            .filterNot { it.viaTag }
+            .map { it.id }
+            .toSet()
+    val viaTag =
+        note.labels
+            .filter { it.viaTag }
+            .map { it.id }
+            .toSet()
+
+    ModalBottomSheet(onDismissRequest = onDismiss) {
+        Column(
+            modifier =
+                Modifier
+                    .fillMaxWidth()
+                    .padding(horizontal = 16.dp)
+                    .imePadding()
+                    .navigationBarsPadding(),
+        ) {
+            SheetTitle(R.string.label_picker_title)
+
+            PlainTextField(
+                value = typed,
+                onValueChange = { typed = it },
+                hint = R.string.label_new_hint,
+                singleLine = true,
+                keyboardOptions = KeyboardOptions(imeAction = ImeAction.Done),
+                keyboardActions =
+                    KeyboardActions(onDone = {
+                        onAction(EditorAction.CreateLabel(typed))
+                        typed = ""
+                    }),
+            )
+
+            // Capped rather than unbounded: a sheet that grows past the screen
+            // makes its own scroll fight the sheet's drag gesture.
+            LazyColumn(modifier = Modifier.heightIn(max = LABEL_LIST_MAX_HEIGHT)) {
+                items(items = labels, key = { it.id }) { label ->
+                    val fromTag = label.id in viaTag
+                    Row(verticalAlignment = Alignment.CenterVertically) {
+                        Checkbox(
+                            checked = fromTag || label.id in manual,
+                            enabled = !fromTag,
+                            onCheckedChange = { on ->
+                                val next = if (on) manual + label.id else manual - label.id
+                                onAction(EditorAction.SetLabels(next.toList()))
+                            },
+                        )
+                        Text(
+                            text = label.name,
+                            style = MaterialTheme.typography.bodyLarge,
+                            modifier = Modifier.padding(start = 4.dp),
+                        )
+                        if (fromTag) {
+                            Text(
+                                text = stringResource(R.string.label_from_tag),
+                                style = MaterialTheme.typography.labelSmall,
+                                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                                modifier = Modifier.padding(start = 8.dp),
+                            )
+                        }
+                    }
+                }
+            }
+
+            if (labels.isEmpty()) {
+                Text(
+                    text = stringResource(R.string.label_none_body),
+                    style = MaterialTheme.typography.bodyMedium,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    modifier = Modifier.padding(vertical = 16.dp),
+                )
+            }
+        }
+    }
+}
+
+/**
+ * When to be reminded.
+ *
+ * Presets first, and a full picker behind them. On a phone almost every reminder
+ * is "this evening", "tomorrow morning" or "next week" — the web's raw
+ * `datetime-local` field is the right control for a desktop and three taps too
+ * many for the common case here. The exact picker is still there, one tap down,
+ * because "Thursday at 3" is a real thing to want.
+ */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun ReminderSheet(
+    note: Note,
+    onAction: (EditorAction) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    var exact by remember { mutableStateOf(false) }
+
+    ModalBottomSheet(onDismissRequest = onDismiss) {
+        Column(
+            modifier =
+                Modifier
+                    .fillMaxWidth()
+                    .padding(horizontal = 16.dp)
+                    .navigationBarsPadding(),
+        ) {
+            SheetTitle(R.string.reminder_title)
+
+            reminderPresets().forEach { (labelRes, at) ->
+                Text(
+                    text = "${stringResource(labelRes)} · ${formatReminder(rfc3339(at))}",
+                    style = MaterialTheme.typography.bodyLarge,
+                    modifier =
+                        Modifier
+                            .fillMaxWidth()
+                            .clickable {
+                                onAction(EditorAction.SetReminder(rfc3339(at)))
+                                onDismiss()
+                            }.padding(vertical = 12.dp),
+                )
+            }
+
+            Text(
+                text = stringResource(R.string.reminder_pick),
+                style = MaterialTheme.typography.bodyLarge,
+                modifier =
+                    Modifier
+                        .fillMaxWidth()
+                        .clickable { exact = true }
+                        .padding(vertical = 12.dp),
+            )
+
+            // Repeat only appears once there IS a reminder — a recurrence rule on
+            // a note with no time to recur from is a setting that does nothing.
+            if (note.remindAt != null) {
+                RecurrenceChips(
+                    current = note.recurrence,
+                    onPick = { onAction(EditorAction.SetRecurrence(it)) },
+                )
+                Text(
+                    text = stringResource(R.string.reminder_clear),
+                    style = MaterialTheme.typography.bodyLarge,
+                    color = MaterialTheme.colorScheme.error,
+                    modifier =
+                        Modifier
+                            .fillMaxWidth()
+                            .clickable {
+                                onAction(EditorAction.ClearReminder)
+                                onDismiss()
+                            }.padding(vertical = 12.dp),
+                )
+            }
+        }
+    }
+
+    if (exact) {
+        ExactReminderPicker(
+            initial = note.remindAt?.let { localTime(it) } ?: defaultPickerTime(),
+            onPick = {
+                onAction(EditorAction.SetReminder(rfc3339(it)))
+                exact = false
+                onDismiss()
+            },
+            onDismiss = { exact = false },
+        )
+    }
+}
+
+/**
+ * Date then time, as two dialogs.
+ *
+ * Material 3 ships a date picker and a time picker but nothing that does both, and
+ * a phone screen has no room for them side by side. Sequential also matches how
+ * the choice is actually made — you know the day before you know the hour.
+ */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+private fun ExactReminderPicker(
+    initial: LocalDateTime,
+    onPick: (LocalDateTime) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    var date by remember { mutableStateOf<LocalDate?>(null) }
+
+    if (date == null) {
+        val state =
+            rememberDatePickerState(
+                initialSelectedDateMillis =
+                    initial
+                        .toLocalDate()
+                        .atStartOfDay(ZoneId.of("UTC"))
+                        .toInstant()
+                        .toEpochMilli(),
+            )
+        DatePickerDialog(
+            onDismissRequest = onDismiss,
+            confirmButton = {
+                TextButton(
+                    // Nothing selected means nothing to confirm — the picker opens
+                    // on a date, so this only guards a user who cleared it.
+                    enabled = state.selectedDateMillis != null,
+                    onClick = {
+                        // The picker reports UTC midnight of the CALENDAR day that
+                        // was tapped, so it has to be read back in UTC. Reading it
+                        // in the device's zone shifts the date by one west of
+                        // Greenwich — the classic off-by-a-day in this control.
+                        date =
+                            state.selectedDateMillis?.let {
+                                Instant.ofEpochMilli(it).atZone(ZoneId.of("UTC")).toLocalDate()
+                            }
+                    },
+                ) { Text(stringResource(R.string.picker_next)) }
+            },
+            dismissButton = {
+                TextButton(onClick = onDismiss) { Text(stringResource(R.string.editor_cancel)) }
+            },
+        ) {
+            DatePicker(state = state)
+        }
+    } else {
+        val state =
+            rememberTimePickerState(
+                initialHour = initial.hour,
+                initialMinute = initial.minute,
+            )
+        AlertDialog(
+            onDismissRequest = onDismiss,
+            title = { Text(stringResource(R.string.picker_time_title)) },
+            text = { TimePicker(state = state) },
+            confirmButton = {
+                TextButton(onClick = {
+                    onPick(
+                        LocalDateTime.of(
+                            requireNotNull(date) { "the time step is only reachable with a date" },
+                            LocalTime.of(state.hour, state.minute),
+                        ),
+                    )
+                }) { Text(stringResource(R.string.picker_set)) }
+            },
+            dismissButton = {
+                TextButton(onClick = onDismiss) { Text(stringResource(R.string.editor_cancel)) }
+            },
+        )
+    }
+}
+
+@Composable
+private fun RecurrenceChips(
+    current: String?,
+    onPick: (String?) -> Unit,
+) {
+    Row(
+        horizontalArrangement = Arrangement.spacedBy(6.dp),
+        modifier = Modifier.padding(vertical = 8.dp),
+    ) {
+        RECURRENCE_RULES.forEach { (rule, labelRes) ->
+            FilterChip(
+                selected = current.orEmpty() == rule.orEmpty(),
+                onClick = { onPick(rule) },
+                label = { Text(stringResource(labelRes)) },
+            )
+        }
+    }
+}
+
+@Composable
+private fun SheetTitle(labelRes: Int) {
+    Text(
+        text = stringResource(labelRes),
+        style = MaterialTheme.typography.titleMedium,
+        modifier = Modifier.padding(bottom = 8.dp),
+    )
+}
+
+/**
+ * The presets, computed against the device clock at the moment the sheet opens.
+ *
+ * "Later today" disappears once the evening has passed rather than silently
+ * meaning tomorrow — an offer that quietly does something else is worse than one
+ * that isn't there.
+ */
+private fun reminderPresets(): List<Pair<Int, LocalDateTime>> {
+    val now = LocalDateTime.now()
+    val presets = mutableListOf<Pair<Int, LocalDateTime>>()
+    val evening = now.toLocalDate().atTime(EVENING_HOUR, 0)
+    if (evening.isAfter(now)) {
+        presets += R.string.reminder_later_today to evening
+    }
+    presets += R.string.reminder_tomorrow to now.toLocalDate().plusDays(1).atTime(MORNING_HOUR, 0)
+    presets +=
+        R.string.reminder_next_week to
+        now
+            .toLocalDate()
+            .with(TemporalAdjusters.next(DayOfWeek.MONDAY))
+            .atTime(MORNING_HOUR, 0)
+    return presets
+}
+
+/** Where the exact picker opens when the note has no reminder yet. */
+private fun defaultPickerTime(): LocalDateTime =
+    LocalDateTime
+        .now()
+        .toLocalDate()
+        .plusDays(1)
+        .atTime(MORNING_HOUR, 0)
+
+/** The core's recurrence vocabulary; null is "does not repeat". */
+private val RECURRENCE_RULES: List<Pair<String?, Int>> =
+    listOf(
+        null to R.string.recurrence_none,
+        "daily" to R.string.recurrence_daily,
+        "weekly" to R.string.recurrence_weekly,
+        "monthly" to R.string.recurrence_monthly,
+        "yearly" to R.string.recurrence_yearly,
+    )
+
+private const val SWATCHES_PER_ROW = 5
+private const val EVENING_HOUR = 18
+private const val MORNING_HOUR = 8
+private val SWATCH_SIZE = 44.dp
+private val LABEL_LIST_MAX_HEIGHT = 320.dp

android/app/src/main/java/com/fabledsword/thoughtsync/ui/ErrorBanner.kt

@@ -0,0 +1,54 @@
+package com.fabledsword.thoughtsync.ui
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.border
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import com.fabledsword.thoughtsync.R
+
+// Shared by the board and the editor.
+//
+// A failed save is most likely to happen WHILE the editor is open — that is where
+// the writes are — so a banner only the board could render meant the one screen
+// that needed it was the one screen without it.
+
+@Composable
+fun ErrorBanner(
+    message: String,
+    onDismiss: () -> Unit,
+) {
+    val dark = isSystemInDarkTheme()
+    val tint = noteTint("red")
+    Row(
+        modifier =
+            Modifier
+                .fillMaxWidth()
+                .padding(horizontal = 12.dp, vertical = 4.dp)
+                .clip(RoundedCornerShape(BANNER_RADIUS))
+                .background(tint.background(dark))
+                .border(1.dp, tint.border(dark), RoundedCornerShape(BANNER_RADIUS))
+                .padding(start = 12.dp),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        Text(
+            text = message,
+            style = MaterialTheme.typography.bodyMedium,
+            modifier = Modifier.weight(1f),
+        )
+        TextButton(onClick = onDismiss) { Text(stringResource(R.string.error_dismiss)) }
+    }
+}
+
+private val BANNER_RADIUS = 12.dp

android/app/src/main/java/com/fabledsword/thoughtsync/ui/NoteCard.kt

@@ -2,6 +2,7 @@ package com.fabledsword.thoughtsync.ui
 
 import androidx.compose.foundation.background
 import androidx.compose.foundation.border
+import androidx.compose.foundation.clickable
 import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
@@ -28,12 +29,12 @@ import com.fabledsword.thoughtsync.R
 import com.fabledsword.thoughtsync.core.ChecklistItem
 import com.fabledsword.thoughtsync.core.Note
 import com.fabledsword.thoughtsync.core.NoteLabel
-import java.time.OffsetDateTime
-import java.time.format.DateTimeFormatter
-import java.time.format.FormatStyle
 
 @Composable
-fun NoteCard(note: Note) {
+fun NoteCard(
+    note: Note,
+    onOpen: () -> Unit,
+) {
     val dark = isSystemInDarkTheme()
     val tint = noteTint(note.color)
 
@@ -41,7 +42,10 @@ fun NoteCard(note: Note) {
         modifier =
             Modifier
                 .fillMaxWidth()
+                // Clipped BEFORE clickable, so the ripple is bounded by the card's
+                // rounded corners instead of a rectangle overhanging them.
                 .clip(RoundedCornerShape(CARD_RADIUS))
+                .clickable(onClickLabel = stringResource(R.string.board_open_note), onClick = onOpen)
                 .background(tint.background(dark))
                 .border(1.dp, tint.border(dark), RoundedCornerShape(CARD_RADIUS))
                 .padding(12.dp),
@@ -60,7 +64,7 @@ fun NoteCard(note: Note) {
             Spacer(Modifier.height(4.dp))
         }
 
-        if (note.kind == KIND_CHECKLIST) {
+        if (note.kind == KIND_LIST) {
             Checklist(items = note.items)
         } else if (note.body.isNotBlank()) {
             Text(
@@ -158,21 +162,23 @@ private fun LabelChips(labels: List<NoteLabel>) {
     }
 }
 
+/**
+ * The reminder, red once it has passed.
+ *
+ * Red for overdue and neutral otherwise, matching the web card exactly — the same
+ * red-100/red-700 and black/5 pairs, resolved through the shared tint table. It
+ * used to be blue for every reminder here, which made "you missed this" and
+ * "coming up on Friday" look identical on a board full of both.
+ */
 @Composable
 private fun ReminderChip(
     instant: String,
     recurrence: String?,
 ) {
     val dark = isSystemInDarkTheme()
-    val tint = noteTint("blue")
-    val text =
-        buildString {
-            append("⏰ ")
-            append(formatReminder(instant))
-            if (!recurrence.isNullOrBlank()) append(" · ↻ ").also { append(recurrence) }
-        }
+    val tint = noteTint(if (isPast(instant)) "red" else "default")
     Text(
-        text = text,
+        text = reminderLabel(instant, recurrence),
         style = MaterialTheme.typography.labelSmall,
         color = tint.chipForeground(dark),
         maxLines = 1,
@@ -185,23 +191,6 @@ private fun ReminderChip(
     )
 }
 
-/**
- * Render an RFC3339 timestamp in the device's own locale and zone.
- *
- * The core stores and syncs RFC3339 because that is what SQLite holds and what the
- * server speaks; deciding how a human should read it is the UI's job, and the
- * answer differs per device. A string we cannot parse is shown verbatim rather
- * than swallowed — a visibly odd reminder beats a silently missing one.
- */
-private fun formatReminder(raw: String): String =
-    runCatching {
-        OffsetDateTime
-            .parse(raw)
-            .toLocalDateTime()
-            .format(DateTimeFormatter.ofLocalizedDateTime(FormatStyle.MEDIUM, FormatStyle.SHORT))
-    }.getOrDefault(raw)
-
-private const val KIND_CHECKLIST = "list"
 private const val MAX_PREVIEW_LINES = 8
 private const val MAX_CHECKLIST_ROWS = 8
 private const val MAX_LABEL_CHIPS = 3

android/app/src/main/java/com/fabledsword/thoughtsync/ui/NoteEditorScreen.kt

@@ -0,0 +1,314 @@
+package com.fabledsword.thoughtsync.ui
+
+import androidx.activity.compose.BackHandler
+import androidx.annotation.StringRes
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.imePadding
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.LinearProgressIndicator
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.material3.TopAppBar
+import androidx.compose.material3.TopAppBarDefaults
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberUpdatedState
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleEventObserver
+import androidx.lifecycle.compose.LocalLifecycleOwner
+import com.fabledsword.thoughtsync.R
+import com.fabledsword.thoughtsync.core.Label
+import com.fabledsword.thoughtsync.core.Note
+
+/**
+ * The note editor: a full screen, not a sheet.
+ *
+ * A sheet works for capture, where the board behind it is reassurance that the
+ * thought landed somewhere. Editing is different — a sustained task with the
+ * keyboard up — and a sheet would spend the whole time fighting the IME for the
+ * bottom half of the display. Full screen also gives the actions a bottom bar,
+ * which is where a thumb already is.
+ *
+ * The note's own colour paints the WHOLE screen rather than a card inside it, so
+ * opening a note reads as the same object growing to fill the display.
+ */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun NoteEditorScreen(
+    note: Note,
+    labels: List<Label>,
+    saving: Boolean,
+    error: String?,
+    onAction: (EditorAction) -> Unit,
+) {
+    val dark = isSystemInDarkTheme()
+    val tint = noteTint(note.color)
+
+    // Keyed by note id: the editor is reused across notes, and without the key the
+    // second note opened would show the first one's text.
+    var title by remember(note.id) { mutableStateOf(note.title.orEmpty()) }
+    var body by remember(note.id) { mutableStateOf(note.body) }
+    var picker by remember(note.id) { mutableStateOf(Picker.NONE) }
+    var confirmingDelete by remember(note.id) { mutableStateOf(false) }
+
+    // A note in the trash is a record, not a document: editing one would silently
+    // resurrect work that was meant to be thrown away. It renders read-only, with
+    // Restore and Delete forever as the only things to do with it.
+    val readOnly = note.trashed
+
+    // Persist the text, if it changed. The baseline check is what makes "open a
+    // note, read it, back out" write nothing at all — without it every glance
+    // would bump `updated_at`, mark the note dirty for sync, and snapshot a
+    // revision identical to the one before it.
+    val flush = {
+        if (!readOnly && (title != note.title.orEmpty() || body != note.body)) {
+            onAction(EditorAction.SaveText(title, body))
+        }
+    }
+    val leave = {
+        flush()
+        onAction(EditorAction.Close)
+    }
+
+    BackHandler(onBack = leave)
+
+    // Leaving the APP is not closing the editor, so the text has to be saved
+    // without the screen being torn down. Losing a paragraph to an incoming call
+    // is exactly the failure that makes someone stop trusting a notes app.
+    FlushOnStop(flush)
+
+    Scaffold(
+        containerColor = tint.background(dark),
+        topBar = {
+            TopAppBar(
+                title = {},
+                navigationIcon = {
+                    IconButton(onClick = leave) {
+                        Icon(
+                            Icons.AutoMirrored.Filled.ArrowBack,
+                            contentDescription = stringResource(R.string.editor_back),
+                        )
+                    }
+                },
+                colors = TopAppBarDefaults.topAppBarColors(containerColor = tint.background(dark)),
+            )
+        },
+        bottomBar = {
+            EditorBottomBar(
+                note = note,
+                readOnly = readOnly,
+                tint = tint,
+                onPicker = { picker = it },
+                onConfirmDelete = { confirmingDelete = true },
+                onAction = onAction,
+            )
+        },
+    ) { padding ->
+        Column(
+            modifier =
+                Modifier
+                    .fillMaxSize()
+                    .padding(padding)
+                    .imePadding()
+                    .verticalScroll(rememberScrollState())
+                    .padding(horizontal = 16.dp),
+        ) {
+            // A one-pixel line, not a spinner: a save slow enough to see is worth
+            // showing, and one that isn't must not make the screen jump.
+            if (saving) {
+                LinearProgressIndicator(modifier = Modifier.fillMaxWidth())
+            }
+
+            // A failed save has to be visible HERE. The board renders the same
+            // banner, but a write that fails while the editor is open would
+            // otherwise report itself only after the user had already left.
+            error?.let { message ->
+                ErrorBanner(message = message, onDismiss = { onAction(EditorAction.DismissError) })
+            }
+
+            EditorField(
+                value = title,
+                onValueChange = { title = it },
+                hint = R.string.editor_title_hint,
+                enabled = !readOnly,
+                bold = true,
+            )
+
+            if (note.kind == KIND_LIST) {
+                ChecklistEditor(note = note, readOnly = readOnly, onAction = onAction)
+            } else {
+                EditorField(
+                    value = body,
+                    onValueChange = { body = it },
+                    hint = R.string.editor_body_hint,
+                    enabled = !readOnly,
+                    minLines = MIN_BODY_LINES,
+                )
+            }
+
+            if (note.labels.isNotEmpty()) {
+                EditorLabelRow(note = note, readOnly = readOnly, onAction = onAction)
+            }
+
+            note.remindAt?.let { at ->
+                EditorReminderRow(
+                    at = at,
+                    recurrence = note.recurrence,
+                    readOnly = readOnly,
+                    onAction = onAction,
+                )
+            }
+        }
+    }
+
+    EditorOverlays(
+        note = note,
+        labels = labels,
+        picker = picker,
+        onPicker = { picker = it },
+        onAction = onAction,
+    )
+
+    if (confirmingDelete) {
+        // The only irreversible action in the app earns the only confirmation in
+        // it. Everything else — archive, trash, even unlinking a server — undoes.
+        AlertDialog(
+            onDismissRequest = { confirmingDelete = false },
+            title = { Text(stringResource(R.string.editor_delete_forever_title)) },
+            text = { Text(stringResource(R.string.editor_delete_forever_body)) },
+            confirmButton = {
+                TextButton(onClick = {
+                    confirmingDelete = false
+                    onAction(EditorAction.DeleteForever)
+                }) {
+                    Text(stringResource(R.string.editor_delete_forever_confirm))
+                }
+            },
+            dismissButton = {
+                TextButton(onClick = { confirmingDelete = false }) {
+                    Text(stringResource(R.string.editor_cancel))
+                }
+            },
+        )
+    }
+}
+
+/** Which overlay is open. One at a time, so they cannot stack on a phone screen. */
+enum class Picker { NONE, COLOR, LABELS, REMINDER }
+
+/** The pickers, hoisted out so the screen above reads as a layout rather than a switch. */
+@Composable
+private fun EditorOverlays(
+    note: Note,
+    labels: List<Label>,
+    picker: Picker,
+    onPicker: (Picker) -> Unit,
+    onAction: (EditorAction) -> Unit,
+) {
+    val dismiss = { onPicker(Picker.NONE) }
+    when (picker) {
+        Picker.NONE -> Unit
+        Picker.COLOR ->
+            ColorSheet(
+                selected = note.color,
+                onPick = {
+                    onAction(EditorAction.SetColor(it))
+                    dismiss()
+                },
+                onDismiss = dismiss,
+            )
+        Picker.LABELS ->
+            LabelSheet(
+                note = note,
+                labels = labels,
+                onAction = onAction,
+                onDismiss = dismiss,
+            )
+        Picker.REMINDER ->
+            ReminderSheet(
+                note = note,
+                onAction = onAction,
+                onDismiss = dismiss,
+            )
+    }
+}
+
+/**
+ * Run [flush] when the app goes to the background.
+ *
+ * `ON_STOP` rather than `ON_PAUSE`: pause also fires when a dialog opens over the
+ * activity, which would save mid-sentence for no reason. The lambda goes through
+ * `rememberUpdatedState` so the observer — registered once — always calls the
+ * CURRENT one; captured directly it would hold the first composition's empty text
+ * forever and save that over a full note.
+ */
+@Composable
+private fun FlushOnStop(flush: () -> Unit) {
+    val current by rememberUpdatedState(flush)
+    val owner = LocalLifecycleOwner.current
+    DisposableEffect(owner) {
+        val observer =
+            LifecycleEventObserver { _, event ->
+                if (event == Lifecycle.Event.ON_STOP) current()
+            }
+        owner.lifecycle.addObserver(observer)
+        onDispose { owner.lifecycle.removeObserver(observer) }
+    }
+}
+
+/**
+ * The title and body fields.
+ *
+ * Undecorated, via the shared [PlainTextField]: the screen is already painted in
+ * the note's colour, and a filled field would draw a second surface over the first
+ * and turn a note into a form.
+ */
+@Composable
+private fun EditorField(
+    value: String,
+    onValueChange: (String) -> Unit,
+    @StringRes hint: Int,
+    enabled: Boolean,
+    bold: Boolean = false,
+    minLines: Int = 1,
+) {
+    PlainTextField(
+        value = value,
+        onValueChange = onValueChange,
+        hint = hint,
+        enabled = enabled,
+        // The title is one line by contract — it is a name, and a name that wraps
+        // has become a body. The body itself never is.
+        singleLine = bold,
+        minLines = minLines,
+        textStyle =
+            if (bold) {
+                MaterialTheme.typography.titleLarge.copy(fontWeight = FontWeight.SemiBold)
+            } else {
+                MaterialTheme.typography.bodyLarge
+            },
+    )
+}
+
+private const val MIN_BODY_LINES = 6

android/app/src/main/java/com/fabledsword/thoughtsync/ui/NoteKind.kt

@@ -0,0 +1,16 @@
+package com.fabledsword.thoughtsync.ui
+
+/**
+ * The core's `kind` vocabulary, which the UI has to match exactly.
+ *
+ * Shared rather than repeated because it was already living in three places — the
+ * card deciding whether to draw checkboxes, the editor deciding which field to
+ * show, and the view model deciding what to create — and a typo in any one of them
+ * would silently render a checklist as a paragraph rather than fail.
+ *
+ * Strings and not an enum: this is a value the STORE owns, arriving from a server
+ * that may be newer than this client, and an unrecognised kind has to fall through
+ * to "render it as a note" rather than throw.
+ */
+internal const val KIND_TEXT = "text"
+internal const val KIND_LIST = "list"

android/app/src/main/java/com/fabledsword/thoughtsync/ui/PlainField.kt

@@ -0,0 +1,72 @@
+package com.fabledsword.thoughtsync.ui
+
+import androidx.annotation.StringRes
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.text.KeyboardActions
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.LocalTextStyle
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextField
+import androidx.compose.material3.TextFieldDefaults
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.TextStyle
+
+/**
+ * A text field with no box around it.
+ *
+ * Every writing surface in the app — the capture sheet, the editor's title and
+ * body, each checklist row — sits on a surface that already has its own edges and
+ * its own colour. Material's filled field would draw a second, differently
+ * coloured box inside the first, which makes writing a note look like filling in a
+ * form. Stripping the container and the indicator in four places independently is
+ * how they drift apart, so it happens once, here.
+ *
+ * The disabled colours are stripped too: a trashed note is shown through this
+ * field read-only, and Material's disabled treatment would grey out text the user
+ * is meant to be reading.
+ */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun PlainTextField(
+    value: String,
+    onValueChange: (String) -> Unit,
+    modifier: Modifier = Modifier,
+    @StringRes hint: Int? = null,
+    enabled: Boolean = true,
+    singleLine: Boolean = false,
+    minLines: Int = 1,
+    textStyle: TextStyle = LocalTextStyle.current,
+    keyboardOptions: KeyboardOptions = KeyboardOptions.Default,
+    keyboardActions: KeyboardActions = KeyboardActions.Default,
+) {
+    TextField(
+        value = value,
+        onValueChange = onValueChange,
+        modifier = modifier.fillMaxWidth(),
+        enabled = enabled,
+        placeholder = hint?.let { { Text(stringResource(it)) } },
+        singleLine = singleLine,
+        minLines = minLines,
+        textStyle = textStyle,
+        keyboardOptions = keyboardOptions,
+        keyboardActions = keyboardActions,
+        colors =
+            TextFieldDefaults.colors(
+                // Full-strength, not Material's 38%-alpha disabled treatment: a
+                // trashed note is rendered read-only through this field and its
+                // text is meant to be READ, not visually retired.
+                disabledTextColor = MaterialTheme.colorScheme.onSurface,
+                focusedContainerColor = Color.Transparent,
+                unfocusedContainerColor = Color.Transparent,
+                disabledContainerColor = Color.Transparent,
+                focusedIndicatorColor = Color.Transparent,
+                unfocusedIndicatorColor = Color.Transparent,
+                disabledIndicatorColor = Color.Transparent,
+            ),
+    )
+}

android/app/src/main/java/com/fabledsword/thoughtsync/ui/Time.kt

@@ -0,0 +1,69 @@
+package com.fabledsword.thoughtsync.ui
+
+import java.time.Instant
+import java.time.LocalDateTime
+import java.time.OffsetDateTime
+import java.time.ZoneId
+import java.time.format.DateTimeFormatter
+import java.time.format.FormatStyle
+
+// The timestamp seam between the core and the phone.
+//
+// The core stores and syncs RFC3339 in UTC, because that is what SQLite holds and
+// what the server speaks. Deciding how a human should READ an instant is the UI's
+// job and the answer differs per device, so the conversion lives here — once,
+// rather than in the card and the editor separately, where the two would
+// eventually format the same reminder differently.
+
+/**
+ * Exactly the shape the core writes: UTC, milliseconds, `Z`.
+ *
+ * `Instant.toString()` would also be valid RFC3339, but it varies its precision
+ * with the value — it drops the fractional part on a whole second. Matching the
+ * core's `to_rfc3339_opts(Millis, true)` byte for byte means a reminder set on the
+ * phone is indistinguishable from one set on the desktop, including to anything
+ * downstream that compares the strings rather than parsing them.
+ */
+private val RFC3339_UTC: DateTimeFormatter =
+    DateTimeFormatter
+        .ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'")
+        .withZone(ZoneId.of("UTC"))
+
+/** A local wall-clock time, as the instant the core will store. */
+fun rfc3339(local: LocalDateTime): String = RFC3339_UTC.format(local.atZone(ZoneId.systemDefault()).toInstant())
+
+/** An instant from the core, as this device's local wall-clock time. */
+fun localTime(raw: String): LocalDateTime? =
+    runCatching {
+        OffsetDateTime.parse(raw).atZoneSameInstant(ZoneId.systemDefault()).toLocalDateTime()
+    }.getOrNull()
+
+/**
+ * A stored instant in the device's own locale and zone.
+ *
+ * A string we cannot parse is shown verbatim rather than swallowed: a visibly odd
+ * reminder beats a silently missing one, and the raw value is what someone would
+ * need in order to report it.
+ */
+fun formatReminder(raw: String): String =
+    localTime(raw)
+        ?.format(DateTimeFormatter.ofLocalizedDateTime(FormatStyle.MEDIUM, FormatStyle.SHORT))
+        ?: raw
+
+/** The reminder as one line, with its repeat rule if it has one. */
+fun reminderLabel(
+    raw: String,
+    recurrence: String?,
+): String =
+    buildString {
+        append("⏰ ")
+        append(formatReminder(raw))
+        if (!recurrence.isNullOrBlank()) {
+            append(" · ↻ ")
+            append(recurrence)
+        }
+    }
+
+/** Whether a stored reminder has already passed, for showing it as overdue. */
+fun isPast(raw: String): Boolean =
+    runCatching { OffsetDateTime.parse(raw).toInstant() < Instant.now() }.getOrDefault(false)

android/app/src/main/res/values/strings.xml

@@ -38,6 +38,60 @@
     <string name="empty_reminders_title">No reminders</string>
     <string name="empty_reminders_body">Notes with a reminder set will appear here.</string>
 
+    <!-- Editor -->
+    <string name="board_open_note">Open note</string>
+    <string name="editor_back">Back to notes</string>
+    <string name="editor_title_hint">Title</string>
+    <string name="editor_body_hint">Note</string>
+    <string name="editor_add_item">Add item</string>
+    <string name="editor_remove_item">Remove item</string>
+    <string name="editor_remove_label">Remove label</string>
+    <string name="editor_reminder">Set a reminder</string>
+    <string name="editor_make_list">Make a checklist</string>
+    <string name="editor_make_note">Switch to a note</string>
+    <string name="editor_more">More actions</string>
+    <string name="editor_pin">Pin</string>
+    <string name="editor_unpin">Unpin</string>
+    <string name="editor_labels">Labels…</string>
+    <string name="editor_archive">Archive</string>
+    <string name="editor_unarchive">Unarchive</string>
+    <string name="editor_trash">Move to trash</string>
+    <string name="editor_restore">Restore</string>
+    <string name="editor_cancel">Cancel</string>
+
+    <!-- Deleting for good is the only thing in the app that cannot be undone, so
+         the copy says exactly that rather than asking "Are you sure?". -->
+    <string name="editor_delete_forever">Delete forever</string>
+    <string name="editor_delete_forever_title">Delete this note?</string>
+    <string name="editor_delete_forever_body">It will be removed from this device and from every device you sync with. This cannot be undone.</string>
+    <string name="editor_delete_forever_confirm">Delete</string>
+
+    <!-- Pickers -->
+    <string name="color_picker_title">Color</string>
+    <string name="label_picker_title">Labels</string>
+    <string name="label_new_hint">Type a label and press enter</string>
+    <string name="label_from_tag">from #tag</string>
+    <string name="label_none_body">No labels yet. Type one above, or write a #tag in a note and it becomes one.</string>
+    <string name="picker_next">Next</string>
+    <string name="picker_set">Set</string>
+    <string name="picker_time_title">Pick a time</string>
+
+    <!-- Reminders -->
+    <string name="reminder_title">Remind me</string>
+    <string name="reminder_later_today">Later today</string>
+    <string name="reminder_tomorrow">Tomorrow</string>
+    <string name="reminder_next_week">Next week</string>
+    <string name="reminder_pick">Pick a date &amp; time</string>
+    <string name="reminder_clear">Remove reminder</string>
+    <string name="reminder_done">Done</string>
+    <string name="reminder_snooze_hour">Snooze 1h</string>
+    <string name="reminder_snooze_day">Snooze 1d</string>
+    <string name="recurrence_none">Once</string>
+    <string name="recurrence_daily">Daily</string>
+    <string name="recurrence_weekly">Weekly</string>
+    <string name="recurrence_monthly">Monthly</string>
+    <string name="recurrence_yearly">Yearly</string>
+
     <!-- Store failure -->
     <string name="store_unavailable_title">Your notes couldn\'t be opened</string>
     <string name="store_unavailable_body">The note store on this device could not be read. Reinstalling will start a fresh one, but anything not synced to a server would be lost.</string>

android/config/detekt.yml

@@ -24,6 +24,29 @@ style:
     # constant.
     ignorePropertyDeclaration: true
 
+complexity:
+  # Compose breaks the PREMISE of both rules below, not just their thresholds.
+  #
+  #   * LongParameterList assumes a long list means an over-general function. A
+  #     composable's parameters ARE its UI contract — Material's own TextField
+  #     takes twenty — and collapsing them into a parameter object makes the call
+  #     site worse, not better, because named arguments are what keep a Compose
+  #     tree readable.
+  #   * LongMethod assumes length tracks branching. A composable's length tracks
+  #     how many ELEMENTS are on the screen; a full-screen editor with a title, a
+  #     body, a checklist, labels and a reminder row is long because it renders
+  #     five things, and cutting it into five one-call wrappers would add
+  #     indirection without removing a single decision.
+  #
+  # Scoped to @Composable rather than disabled: on ordinary functions both rules
+  # are right, and one of them still fires below (see BoardViewModel).
+  LongParameterList:
+    ignoreAnnotated:
+      - "Composable"
+  LongMethod:
+    ignoreAnnotated:
+      - "Composable"
+
 exceptions:
   TooGenericExceptionCaught:
     # Catching broadly is DELIBERATE in these two places, and each site says so.

android/ffi/src/lib.rs

@@ -212,6 +212,127 @@ impl ThoughtSync {
             .map_err(CoreError::store)
     }
 
+    /// Remove a note permanently.
+    ///
+    /// Returns nothing, unlike every other mutation here: there is no note left to
+    /// return. The core also records a pending delete, so a linked device tells the
+    /// server rather than having the next pull resurrect the row.
+    pub fn delete_note_forever(&self, id: String) -> Result<(), CoreError> {
+        let conn = self.db.conn().map_err(CoreError::store)?;
+        local::store::delete_forever(&conn, &id).map_err(CoreError::store)
+    }
+
+    // ────────────────────────────  checklist items  ────────────────────────────
+    //
+    // Every one of these returns the whole reloaded note rather than the item it
+    // touched. That is the core's shape, and it is the right one for a UI: ticking
+    // a box changes `updated_at` and can change what the board shows, so handing
+    // back only the item would leave Kotlin to guess at the rest.
+
+    pub fn add_item(&self, note_id: String, text: String) -> Result<Note, CoreError> {
+        let conn = self.db.conn().map_err(CoreError::store)?;
+        local::store::add_item(&conn, &note_id, &text)
+            .map(Note::from)
+            .map_err(CoreError::store)
+    }
+
+    /// Retitle one item.
+    ///
+    /// Split from `set_item_checked` rather than exposing the core's
+    /// `{text?, checked?}` patch, for the same reason `NoteEdit` exists: an
+    /// optional-field struct cannot say "leave this alone" in Kotlin without
+    /// colliding with "set it to null", and two unambiguous calls beat one
+    /// ambiguous one when each is three lines.
+    pub fn set_item_text(
+        &self,
+        note_id: String,
+        item_id: String,
+        text: String,
+    ) -> Result<Note, CoreError> {
+        self.patch_item(&note_id, &item_id, serde_json::json!({ "text": text }))
+    }
+
+    pub fn set_item_checked(
+        &self,
+        note_id: String,
+        item_id: String,
+        checked: bool,
+    ) -> Result<Note, CoreError> {
+        self.patch_item(
+            &note_id,
+            &item_id,
+            serde_json::json!({ "checked": checked }),
+        )
+    }
+
+    pub fn delete_item(&self, note_id: String, item_id: String) -> Result<Note, CoreError> {
+        let conn = self.db.conn().map_err(CoreError::store)?;
+        local::store::delete_item(&conn, &note_id, &item_id)
+            .map(Note::from)
+            .map_err(CoreError::store)
+    }
+
+    // ───────────────────────────────  reminders  ───────────────────────────────
+
+    /// Clear the reminder, marking it dealt with.
+    ///
+    /// Distinct from `NoteEdit::ClearRemindAt` even though today they do the same
+    /// thing: the core reserves this one for "the reminder fired and is finished",
+    /// which is where recurrence advancement lands when it is built. A UI that
+    /// called the generic clear instead would silently stop recurring reminders
+    /// from recurring the day that changes.
+    pub fn complete_reminder(&self, id: String) -> Result<Note, CoreError> {
+        let conn = self.db.conn().map_err(CoreError::store)?;
+        local::store::complete_reminder(&conn, &id)
+            .map(Note::from)
+            .map_err(CoreError::store)
+    }
+
+    /// Push the reminder out by `minutes` from now.
+    ///
+    /// The core computes the new instant from its own clock rather than taking one
+    /// from the caller — so "in an hour" means the same thing on every surface,
+    /// and a phone with a skewed clock can't write a reminder the server reads as
+    /// already past.
+    pub fn snooze_reminder(&self, id: String, minutes: i64) -> Result<Note, CoreError> {
+        let conn = self.db.conn().map_err(CoreError::store)?;
+        local::store::snooze_reminder(&conn, &id, minutes)
+            .map(Note::from)
+            .map_err(CoreError::store)
+    }
+
+    // ─────────────────────────────────  labels  ────────────────────────────────
+
+    /// Replace the note's MANUAL labels.
+    ///
+    /// `#tag` labels are owned by the body text and the core re-derives them on
+    /// every body edit, so they are deliberately untouched here. A picker that
+    /// sent the full visible set would strip a tag label the text still mandates —
+    /// and the next keystroke in the body would put it straight back, which is the
+    /// kind of fight a UI should never pick with its store.
+    pub fn set_note_labels(
+        &self,
+        note_id: String,
+        label_ids: Vec<String>,
+    ) -> Result<Note, CoreError> {
+        let conn = self.db.conn().map_err(CoreError::store)?;
+        local::store::set_labels(&conn, &note_id, &label_ids)
+            .map(Note::from)
+            .map_err(CoreError::store)
+    }
+
+    /// Find or create a label by name, returning it either way.
+    ///
+    /// Find-or-create rather than create: the core matches case-insensitively, so
+    /// typing "Errands" when "errands" exists has to attach the existing label
+    /// instead of minting a near-duplicate that then diverges on colour.
+    pub fn create_label(&self, name: String) -> Result<Label, CoreError> {
+        let conn = self.db.conn().map_err(CoreError::store)?;
+        local::store::create_label(&conn, &name)
+            .map(Label::from)
+            .map_err(CoreError::store)
+    }
+
     // ───────────────────────────────  sync  ────────────────────────────────
 
     pub fn sync_status(&self) -> Result<SyncStatus, CoreError> {
@@ -333,6 +454,22 @@ impl ThoughtSync {
 /// Helpers, deliberately NOT exported — uniffi only binds what an `#[uniffi::export]`
 /// block names, so these stay Rust-side.
 impl ThoughtSync {
+    /// Apply a `{text}` or `{checked}` patch to one checklist item.
+    ///
+    /// The two public setters differ only in the key they write, and the lock +
+    /// convert + map-error dance around it is identical, so it lives once here.
+    fn patch_item(
+        &self,
+        note_id: &str,
+        item_id: &str,
+        changes: serde_json::Value,
+    ) -> Result<Note, CoreError> {
+        let conn = self.db.conn().map_err(CoreError::store)?;
+        local::store::update_item(&conn, note_id, item_id, &changes)
+            .map(Note::from)
+            .map_err(CoreError::store)
+    }
+
     /// The server URL + token, or the `NotLinked` state. Every networked call needs
     /// exactly this, and none of them may hold the lock past it.
     fn credentials(&self) -> Result<(String, String), CoreError> {
@@ -479,4 +616,152 @@ mod tests {
 
         std::fs::remove_dir_all(&dir).ok();
     }
+
+    /// The editor's whole checklist loop, in one pass: add a row, tick it, retitle
+    /// it, drop it. Each call returns the reloaded note, which is what the UI
+    /// splices back into the board rather than re-querying.
+    #[test]
+    fn checklist_items_can_be_added_ticked_retitled_and_removed() {
+        let dir = scratch_dir();
+        let app = ThoughtSync::new(dir.clone()).expect("a fresh data dir should open");
+        let note = app
+            .create_note(NoteDraft {
+                title: "Packing".to_string(),
+                body: String::new(),
+                color: "default".to_string(),
+                kind: Some("list".to_string()),
+                items: Some(vec!["socks".to_string()]),
+            })
+            .expect("create");
+        assert_eq!(note.items.len(), 1);
+
+        let with_two = app
+            .add_item(note.id.clone(), "charger".to_string())
+            .expect("add");
+        assert_eq!(with_two.items.len(), 2);
+        // Appended, not prepended — a new row belongs at the bottom of the list the
+        // user is looking at.
+        assert_eq!(with_two.items[1].text, "charger");
+
+        let item_id = with_two.items[1].id.clone();
+        let ticked = app
+            .set_item_checked(note.id.clone(), item_id.clone(), true)
+            .expect("tick");
+        assert!(ticked.items[1].checked);
+        assert_eq!(
+            ticked.items[1].text, "charger",
+            "ticking a box must not disturb its text — the two setters write \
+             different columns and neither may clear the other"
+        );
+
+        let renamed = app
+            .set_item_text(note.id.clone(), item_id.clone(), "usb-c cable".to_string())
+            .expect("rename");
+        assert_eq!(renamed.items[1].text, "usb-c cable");
+        assert!(
+            renamed.items[1].checked,
+            "and the same in the other direction"
+        );
+
+        let trimmed = app
+            .delete_item(note.id.clone(), item_id)
+            .expect("delete item");
+        assert_eq!(trimmed.items.len(), 1);
+        assert_eq!(trimmed.items[0].text, "socks");
+
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    /// A `#tag` in the body owns its label. The picker replaces MANUAL labels only,
+    /// so sending an empty set must not strip one the text still mandates —
+    /// otherwise the next body edit would re-derive it and the UI would appear to
+    /// fight itself.
+    #[test]
+    fn setting_labels_leaves_tag_derived_ones_alone() {
+        let dir = scratch_dir();
+        let app = ThoughtSync::new(dir.clone()).expect("a fresh data dir should open");
+
+        let note = app
+            .create_note(draft("Trip", "book the ferry #travel"))
+            .expect("create");
+        assert_eq!(
+            note.labels.len(),
+            1,
+            "the #tag should have attached a label"
+        );
+        assert!(note.labels[0].via_tag);
+
+        let errands = app
+            .create_label("errands".to_string())
+            .expect("create label");
+        let tagged = app
+            .set_note_labels(note.id.clone(), vec![errands.id.clone()])
+            .expect("set labels");
+        assert_eq!(tagged.labels.len(), 2);
+
+        let cleared = app
+            .set_note_labels(note.id.clone(), vec![])
+            .expect("clear manual labels");
+        assert_eq!(cleared.labels.len(), 1);
+        assert!(cleared.labels[0].via_tag);
+
+        // Find-or-create, not create: a second "Errands" must be the same label,
+        // or the picker mints near-duplicates that then diverge on colour.
+        let again = app
+            .create_label("Errands".to_string())
+            .expect("create label again");
+        assert_eq!(again.id, errands.id);
+
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    /// Deleting forever has to actually remove the row, and the note must then be
+    /// unreadable rather than merely hidden.
+    #[test]
+    fn deleting_forever_removes_the_note() {
+        let dir = scratch_dir();
+        let app = ThoughtSync::new(dir.clone()).expect("a fresh data dir should open");
+        let note = app.create_note(draft("Ephemeral", "body")).expect("create");
+
+        app.delete_note_forever(note.id.clone())
+            .expect("delete forever");
+        assert!(
+            app.get_note(note.id.clone()).is_err(),
+            "a permanently deleted note must not still load"
+        );
+
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    /// Snooze writes a future instant from the CORE's clock; complete clears it.
+    #[test]
+    fn reminders_can_be_snoozed_and_completed() {
+        let dir = scratch_dir();
+        let app = ThoughtSync::new(dir.clone()).expect("a fresh data dir should open");
+        let note = app.create_note(draft("Call back", "")).expect("create");
+        assert_eq!(note.remind_at, None);
+
+        let snoozed = app.snooze_reminder(note.id.clone(), 60).expect("snooze");
+        let at = snoozed.remind_at.expect("snoozing must set a reminder");
+        let parsed = chrono_free_parse(&at);
+        assert!(
+            parsed > 0,
+            "the reminder must be a parseable RFC3339 instant, got {at:?}"
+        );
+
+        let done = app.complete_reminder(note.id.clone()).expect("complete");
+        assert_eq!(done.remind_at, None);
+
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
+    /// A crude RFC3339 sanity check that doesn't pull a date crate into this
+    /// crate's dev-dependencies to assert one field is well-formed.
+    fn chrono_free_parse(raw: &str) -> usize {
+        if raw.len() >= 20 && raw.as_bytes()[4] == b'-' && raw.contains('T') {
+            raw.len()
+        } else {
+            0
+        }
+    }
 }