Lay the notes panel out by its own width, not the window's

The panel splits master/detail unconditionally: a 192px title column beside
the editor. That fits the Project Home tab and does not fit the dock. At the
dock's 352px default the editor gets 157px, and its action row wants ~200px,
so the Delete button lands outside the dock's `overflow-hidden` with no
scrollbar to reach it, and the textarea collapses to a two-word column.

The two surfaces differ in width while sharing a viewport, so this is a
container query rather than a `md:` breakpoint — a viewport query reads the
window and hands both surfaces the same answer, which is wrong for one of
them. Tailwind v4 has these in core; verified as real
`@container (min-width: 32rem)` rules in the built CSS, since a variant that
silently compiles to nothing looks identical in review.

The threshold is arithmetic: side by side needs the 192px list, an editor
wide enough for its own buttons (~280px), and the divider. `@lg` (512px) is
the first stop clearing ~473px. Below it the titles become a capped strip
above the editor, so the note being written keeps the height.

The action row now wraps, which is the part that holds at *any* width rather
than on one side of a threshold: the buttons are a group that does not shrink,
the title field shrinks to 96px, and past that the title takes one row and the
buttons the next. Nothing can be pushed out of the panel.

Not covered by the suite — jsdom has no layout engine, so 711 tests pass
before and after. This needs eyes on the dock at its minimum, default and
maximum widths.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011YPqHpjV4EL6RNEwrRKqQm

app/src/components/notes/NoteEditor.tsx

@@ -30,15 +30,22 @@ export default function NoteEditor({
 }: Props) {
   return (
     <div className="flex flex-col h-full min-h-0 gap-2 p-3">
-      <div className="flex items-center gap-2">
+      {/* Wraps rather than overflows. The two buttons are a group with a fixed
+          appetite (~190px) and the title field can shrink only so far, so in a
+          narrow dock the title takes the first row and the buttons the second.
+          Without the wrap the group is simply clipped by the dock's
+          `overflow-hidden`, which puts Delete off-window with no scrollbar to
+          reach it. */}
+      <div className="flex flex-wrap items-center gap-2">
         <input
           value={title}
           onChange={(e) => onTitleChange(e.target.value)}
           onBlur={onCommit}
           placeholder="Note title"
           aria-label="Note title"
-          className="flex-1 min-w-0 px-2 h-8 bg-[var(--bg-primary)] border border-[var(--border-color)] rounded-[var(--radius-control)] text-[13px] text-[var(--text-primary)] focus:border-[var(--accent)] transition-colors"
+          className="flex-1 min-w-24 px-2 h-8 bg-[var(--bg-primary)] border border-[var(--border-color)] rounded-[var(--radius-control)] text-[13px] text-[var(--text-primary)] focus:border-[var(--accent)] transition-colors"
         />
+        <div className="flex items-center gap-2 flex-shrink-0">
           {/* The live editor text, not `note.body` — what is on screen is what
               gets sent. */}
           <SendToAgentButton projectId={projectId} body={body} />
@@ -46,6 +53,7 @@ export default function NoteEditor({
             Delete
           </Button>
         </div>
+      </div>
       <textarea
         value={body}
         onChange={(e) => onBodyChange(e.target.value)}

app/src/components/notes/NotesPanel.tsx

@@ -14,9 +14,21 @@ const UNTITLED = "Untitled note";
  * The notes surface itself, shared by the Project Home tab and the dock so the
  * two cannot drift into different behaviour.
  *
- * Master/detail: titles on the left, one editor on the right. The editor holds
- * draft text locally and commits on blur, which is how every other editable
- * field in the app behaves (`ClaudeInstructionsEditor`, the Config tab).
+ * Master/detail: titles beside the editor when there is room, stacked above it
+ * when there is not. That is a **container** query, not a viewport one, because
+ * the two surfaces differ in width while sharing a viewport — the dock opens at
+ * 352px and the tab is the width of the main area. A `md:` breakpoint would
+ * read the window and give both the same answer, which is the wrong answer for
+ * one of them.
+ *
+ * The threshold is arithmetic, not taste: side by side needs the 192px list,
+ * plus an editor wide enough for its own action row (~280px), plus the divider.
+ * Below ~473px the editor is narrower than its buttons, so `@lg` (512px) is the
+ * first stop that clears it.
+ *
+ * The editor holds draft text locally and commits on blur, which is how every
+ * other editable field in the app behaves (`ClaudeInstructionsEditor`, the
+ * Config tab).
  */
 export default function NotesPanel({ projectId }: Props) {
   const { notes, loading, saveState, createNote, saveNote, deleteNote } =
@@ -83,7 +95,7 @@ export default function NotesPanel({ projectId }: Props) {
   }
 
   return (
-    <div className="flex flex-col h-full min-h-0">
+    <div className="@container flex flex-col h-full min-h-0">
       <div className="flex items-center justify-between gap-2 px-3 py-2 border-b border-[var(--border-color)]">
         <Button variant="primary" onClick={onCreate}>
           New note
@@ -99,8 +111,11 @@ export default function NotesPanel({ projectId }: Props) {
           </p>
         </div>
       ) : (
-        <div className="flex-1 min-h-0 flex">
-          <ul className="w-48 flex-shrink-0 overflow-y-auto border-r border-[var(--border-color)] py-1">
+        <div className="flex-1 min-h-0 flex flex-col @lg:flex-row">
+          {/* Stacked: a capped strip of titles above the editor, so the note
+              being written keeps most of the height. Side by side: a full-height
+              column of the fixed width the editor's arithmetic assumes. */}
+          <ul className="flex-shrink-0 overflow-y-auto py-1 max-h-32 border-b @lg:max-h-none @lg:w-48 @lg:border-b-0 @lg:border-r border-[var(--border-color)]">
             {notes.map((n) => (
               <li key={n.id}>
                 <button