Unify compose + edit onto one surface (modal-only editor)

Live-pass feedback: compose and edit still felt like different surfaces.
They already shared one component (task 1920), but rendered as two frames —
an inline in-flow box (compose) vs a modal overlay (edit) — which read as
two designs. Per operator choice, make BOTH the modal.

NoteEditor is now modal-only (rule 22 — the inline frame is fully removed):
dropped the `inline`/`autofocus` props, the collapsed "Take a note" frame,
`expanded`, `open()`, `commitInline`, `autoGrow`, and the outside-click
commit. Compose vs edit is purely note=null vs a note. Esc / Ctrl+Enter /
backdrop / Done all commit-and-close (create in compose, save in edit);
Shift+Enter still saves & starts a fresh note in compose (now gated on
isCreate, not the frame). Edit-only sections gate on !isCreate.

BoardView: the always-expanded inline composer becomes a slim "Take a
note…" trigger bar that opens the SAME modal with an empty note; the `c`
shortcut does likewise. One surface for capture and editing — and the
seam the card→editor grow animation (1914) will hook into.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FRgehjoz7Yv8LkUfADxACm

frontend/src/views/BoardView.vue

@@ -14,14 +14,14 @@ const ui = useUiStore();
 const router = useRouter();
 
 const editing = ref<Note | null>(null);
-const composer = ref<InstanceType<typeof NoteEditor> | null>(null);
+const composing = ref(false); // compose modal open (a new, empty note)
 const loadError = ref("");
 
-// The global `c` shortcut bumps composeTick; reopen the composer when we're
-// already on the board (a fresh navigation autofocuses it via the prop).
+// Compose and edit are ONE surface: the "Take a note…" bar and the global `c`
+// shortcut both open the same modal editor with an empty note (editing = null).
 watch(
   () => ui.composeTick,
-  () => composer.value?.open(),
+  () => (composing.value = true),
 );
 
 // The command palette opens a note by navigating here with ?open=<id>.
@@ -146,6 +146,7 @@ function openEditor(note: Note) {
 }
 function closeEditor() {
   editing.value = null;
+  composing.value = false;
 }
 
 async function onNavigate(id: string) {
@@ -182,7 +183,14 @@ async function onDrop(target: Note) {
 
 <template>
   <div class="mx-auto w-full max-w-6xl px-4 py-6">
-    <NoteEditor v-if="isMainBoard" ref="composer" inline autofocus class="mb-6" />
+    <button
+      v-if="isMainBoard"
+      type="button"
+      class="mx-auto mb-6 block w-full max-w-xl rounded-xl border border-neutral-200 bg-white px-4 py-3 text-left text-sm text-neutral-500 shadow-sm transition hover:shadow-md focus:outline-none focus-visible:ring-2 focus-visible:ring-brand dark:border-neutral-700 dark:bg-neutral-900 dark:text-neutral-400"
+      @click="composing = true"
+    >
+      Take a note…
+    </button>
     <FilterBar v-if="isMainBoard" />
 
     <div v-if="notes.loading" class="py-24 text-center text-sm text-neutral-400">Loading…</div>
@@ -258,7 +266,7 @@ async function onDrop(target: Note) {
     </template>
   </div>
 
-  <template v-if="editing">
+  <template v-if="composing || editing">
     <NoteEditor :note="editing" @close="closeEditor" @navigate="onNavigate" />
   </template>
 </template>