notes: color leaves the model, the wire and all three surfaces

Step 3 of M315, and the destructive half. Steps 1 and 2 stopped every read of
this field: a card is one neutral surface per theme, and the only coloured
thing on a board is a tag. What was left was a column written by a picker and
read by nothing.

Rule 22 — the old path comes out completely. No flag, no fallback, no
"override if set".

Server: the column, the `?color=` facet, the create/update/serialise paths,
the sync assignment, the front-matter line, and Keep's colour map. Alembic
0029 drops it and sweeps `"color"` out of stored saved-filter params — a view
that silently filtered on a field the app no longer has would return nothing
and never say why. That sweep is Python, not `params::jsonb - 'color'`,
because Postgres has no try-cast and one malformed blob would abort a
migration that is running over somebody's saved views.

`NOTE_COLORS` moves from `models/note.py` to `colors.py`. A palette defined on
the model that lost one is an invitation to put the column back; labels still
name a colour, so the vocabulary belongs where the normalizer already is.

Core: the field, the facet, the `NoteCreateInput`, and every read and write in
store/push/pull. Local schema v9 drops the column and does the same
saved-filter sweep, guarded on `json_valid` so a corrupt blob loses a key
rather than becoming NULL. The uniffi layer drops `NoteEdit::Color` and
`NoteDraft.color` with it.

Web: `ColorPicker.vue`, the per-card swatch popover and its stylesheet rule,
the FilterBar colour row, the facet in the query round-trip, and the colour
half of the editor's baseline-and-save. Android: the `ColorSheet`, the
`Picker.COLOR` case, the toolbar's swatch dot, `EditorAction.SetColor`.

## The protocol: v4, and the floor deliberately stays at 3

Checked against `compat.rs` and the push handler rather than trusting the
`#[serde(default)]` annotation, because the v2 precedent points the other way:
v2 dropped `kind` and `title` and DID raise both floors, on the rule that
dropping a field a client sends and expects back is breaking.

`color` fails the second half of that test. A v3 client reading a v4 note gets
`"default"` from its own serde default and draws the colour it derives
locally — the board it drew yesterday. A v3 client pushing `color` has the key
ignored, since `_assign_note_fields` reads its payload key by key and never
validates the shape. Neither direction errors and neither shows anything
wrong. `title` was the note's NAME; this is a field that no longer renders.

So `SYNC_PROTOCOL_VERSION` and `CLIENT_PROTOCOL_VERSION` go to 4, and both
floors stay at 3. `docs/sync.md` carries the reasoning and the per-version
history, and its push example is brought back in line — it still listed
`title`, `kind` and `items`, all gone before this.

Import stays tolerant: a pre-M315 export or a Keep takeout carrying `color:`
imports fine, the key simply read past. Old exports must still import.

#3041

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

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

@@ -354,7 +354,6 @@ class BoardViewModel(
             is EditorAction.SaveText ->
                 mutate { it.updateNote(id, listOf(NoteEdit.Body(action.body))) }
 
-            is EditorAction.SetColor -> edit(id, NoteEdit.Color(action.color))
 
             // 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
@@ -511,9 +510,6 @@ 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
@@ -529,7 +525,7 @@ private fun draft(content: String): NoteDraft =
     // The core names the note from the body's first line, so a captured thought is
     // findable without anyone being asked to name it. A checklist is added afterwards,
     // in the editor — it is something a note HAS, not a different thing to capture.
-    NoteDraft(body = content, color = DEFAULT_COLOR, items = null)
+    NoteDraft(body = content, items = null)
 
 /**
  * The id a note has before it has been saved.
@@ -545,7 +541,6 @@ private fun blankDraft(): Note =
         id = DRAFT_ID,
         displayTitle = "",
         body = "",
-        color = DEFAULT_COLOR,
         position = 0,
         pinned = false,
         archived = false,

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

@@ -25,10 +25,6 @@ sealed interface EditorAction {
         val body: String,
     ) : EditorAction
 
-    data class SetColor(
-        val color: String,
-    ) : EditorAction
-
     data class SetPinned(
         val pinned: Boolean,
     ) : EditorAction

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

@@ -12,7 +12,6 @@ import androidx.compose.foundation.layout.fillMaxWidth
 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.shape.CircleShape
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.ArrowBack
@@ -76,9 +75,6 @@ import com.fabledsword.thoughtsync.core.Note
 fun EditorTopBar(
     note: Note,
     readOnly: Boolean,
-    /** What the colour PICKER is set to — the swatch dot's fill, and nothing else.
-     *  Since M315 no surface paints with a note's colour; see [noteCardSurface]. */
-    picked: NoteTint,
     onClose: () -> Unit,
     onStartChecklist: () -> Unit,
     onPicker: (Picker) -> Unit,
@@ -101,18 +97,6 @@ fun EditorTopBar(
         },
         actions = {
             if (!readOnly) {
-                // A dot in the picker's CURRENT colour rather than a palette icon: it
-                // shows what the setting is as well as what the button does.
-                IconButton(onClick = { onPicker(Picker.COLOR) }) {
-                    Box(
-                        modifier =
-                            Modifier
-                                .size(SWATCH_DOT)
-                                .clip(CircleShape)
-                                .background(picked.chipBackground(dark))
-                                .border(1.dp, picked.border(dark), CircleShape),
-                    )
-                }
                 IconButton(onClick = { onPicker(Picker.REMINDER) }) {
                     Icon(
                         Icons.Filled.Notifications,
@@ -410,6 +394,5 @@ fun EditorReminderRow(
     }
 }
 
-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

@@ -1,11 +1,7 @@
 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.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.fillMaxWidth
@@ -13,21 +9,16 @@ 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
@@ -42,7 +33,6 @@ 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
@@ -57,80 +47,17 @@ 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.
+// The two things you pick rather than type: a set of labels, and a time.
+//
+// It was three. The colour sheet went with `note.color` in M315 — a card is one neutral
+// surface now and colour lives on the tag, so the swatch grid was a control with nothing
+// behind it.
 //
 // 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.
  *
@@ -461,8 +388,6 @@ private val RECURRENCE_RULES: List<Pair<String?, Int>> =
         "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/NoteCard.kt

@@ -179,10 +179,10 @@ fun NoteCard(
  * whatever matches. A menu that offered "Move to trash" on a note already in the
  * trash would be offering to do something twice.
  *
- * **Colour is deliberately absent**, though #2946 suggested it. `note.color` is
- * scheduled for removal along with the whole picker (#3041, the last step of M309) —
- * colour comes from the note's tags now. Building a swatch row here would be building
- * the one control in this menu already known to be coming out.
+ * **Colour is absent**, though #2946 suggested it. It was left out because `note.color`
+ * was already scheduled for removal; M315 removed it. There is no colour to set on a
+ * note any more — a card is one neutral surface and the only coloured thing on a board
+ * is a tag — so the row this menu never grew is a row that could not exist.
  *
  * Labels are absent too, for a duller reason: the picker they open is editor state,
  * and hoisting it to the board is a bigger change than the friction actually reported.

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

@@ -59,10 +59,6 @@ fun NoteEditorScreen(
     onAction: (EditorAction) -> Unit,
 ) {
     val dark = isSystemInDarkTheme()
-    // The colour the PICKER is set to, which since M315 is all `note.color` still is:
-    // nothing paints with it any more. It feeds the swatch dot so the control shows its
-    // own state; both go together in #3041.
-    val picked = noteTint(note.color)
 
     // Keyed by the SESSION, not by note.id: the editor is reused across notes, so it
     // needs a key — but a draft's id changes the moment it is first saved, and
@@ -171,7 +167,6 @@ fun NoteEditorScreen(
                     EditorTopBar(
                         note = note,
                         readOnly = readOnly,
-                        picked = picked,
                         onClose = leave,
                         onStartChecklist = {
                             val (next, id) = blocks.plusTask()
@@ -273,7 +268,7 @@ fun NoteEditorScreen(
 }
 
 /** Which overlay is open. One at a time, so they cannot stack on a phone screen. */
-enum class Picker { NONE, COLOR, LABELS, REMINDER }
+enum class Picker { NONE, LABELS, REMINDER }
 
 /** The pickers, hoisted out so the screen above reads as a layout rather than a switch. */
 @Composable
@@ -287,15 +282,6 @@ private fun EditorOverlays(
     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,

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

@@ -67,7 +67,6 @@
     <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>