feat(notes): persist web note edits

web/src/app/(app)/notes/[noteId]/page.tsx

@@ -9,13 +9,14 @@ import { LinkedNotesPanel } from "@/components/LinkedNotesPanel";
 import { TaskReviewPanel } from "@/components/TaskReviewPanel";
 import { ArtifactPanel } from "@/components/ArtifactPanel";
 import { AgentTimeline } from "@/components/AgentTimeline";
-import { getNoteDetail } from "@/lib/notes-client";
+import { getNoteDetail, updateNoteDetail } from "@/lib/notes-client";
 import type { NoteDetail } from "@/lib/types";
 
 export default function NoteDetailPage() {
   const params = useParams<{ noteId: string }>();
   const noteId = params.noteId;
   const [note, setNote] = useState<NoteDetail | null>(null);
+  const [isSaving, setIsSaving] = useState(false);
   const [error, setError] = useState<string | null>(null);
 
   useEffect(() => {
@@ -28,6 +29,25 @@ export default function NoteDetailPage() {
     })();
   }, [noteId]);
 
+  async function handleSave(updates: { title: string; body: string }) {
+    if (!note) {
+      return;
+    }
+
+    setIsSaving(true);
+
+    try {
+      await updateNoteDetail(note.id, note.workspaceId, updates);
+      const refreshed = await getNoteDetail(note.id);
+      setNote(refreshed);
+      setError(null);
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Unable to save note");
+    } finally {
+      setIsSaving(false);
+    }
+  }
+
   if (!note) {
     return (
       <AppShell
@@ -46,12 +66,13 @@ export default function NoteDetailPage() {
     <AppShell
       title={note.title}
       description="Editable note surface with metadata, linked context, tasks, and artifact placeholders."
-      actions={<div className="badge">Review: {note.metadata.reviewState}</div>}
+      actions={<div className="badge">{isSaving ? "Saving" : `Review: ${note.metadata.reviewState}`}</div>}
     >
       <div style={{ display: "grid", gridTemplateColumns: "minmax(0, 1.7fr) minmax(320px, 1fr)", gap: "var(--ml-space-4)" }}>
-        <NoteEditor note={note} />
+        <NoteEditor note={note} onSave={handleSave} isSaving={isSaving} />
 
         <aside style={{ display: "grid", gap: "var(--ml-space-4)" }}>
+          {error ? <div className="surface-card" style={{ padding: "var(--ml-space-4)", color: "var(--ml-text-secondary)" }}>{error}</div> : null}
           <MetadataPanel note={note} />
           <LinkedNotesPanel linkedNotes={note.linkedNotes} />
           <TaskReviewPanel tasks={note.tasks} />

web/src/components/NoteEditor.tsx

@@ -1,26 +1,74 @@
+import { useEffect, useState } from "react";
 import type { NoteDetail } from "@/lib/types";
 
-export function NoteEditor({ note }: { note: NoteDetail }) {
+export function NoteEditor({
+  note,
+  onSave,
+  isSaving = false,
+}: {
+  note: NoteDetail;
+  onSave: (updates: { title: string; body: string }) => Promise<void>;
+  isSaving?: boolean;
+}) {
+  const [title, setTitle] = useState(note.title);
+  const [body, setBody] = useState(note.body);
+
+  useEffect(() => {
+    setTitle(note.title);
+    setBody(note.body);
+  }, [note.body, note.title]);
+
   return (
     <section className="surface-card" style={{ padding: "var(--ml-space-6)", display: "grid", gap: "var(--ml-space-4)" }}>
-      <div style={{ display: "grid", gap: "var(--ml-space-2)" }}>
-        <label htmlFor="note-title" style={{ color: "var(--ml-text-secondary)" }}>
-          Title
-        </label>
-        <input id="note-title" className="input-shell" defaultValue={note.title} />
-      </div>
+      <form
+        style={{ display: "grid", gap: "var(--ml-space-4)" }}
+        onSubmit={(event) => {
+          event.preventDefault();
+          void onSave({ title, body });
+        }}
+      >
+        <div style={{ display: "grid", gap: "var(--ml-space-2)" }}>
+          <label htmlFor="note-title" style={{ color: "var(--ml-text-secondary)" }}>
+            Title
+          </label>
+          <input
+            id="note-title"
+            className="input-shell"
+            value={title}
+            onChange={(event) => setTitle(event.target.value)}
+          />
+        </div>
 
-      <div style={{ display: "grid", gap: "var(--ml-space-2)" }}>
-        <label htmlFor="note-body" style={{ color: "var(--ml-text-secondary)" }}>
-          Body
-        </label>
-        <textarea
-          id="note-body"
-          className="input-shell"
-          defaultValue={note.body}
-          style={{ minHeight: 360, resize: "vertical" }}
-        />
-      </div>
+        <div style={{ display: "grid", gap: "var(--ml-space-2)" }}>
+          <label htmlFor="note-body" style={{ color: "var(--ml-text-secondary)" }}>
+            Body
+          </label>
+          <textarea
+            id="note-body"
+            className="input-shell"
+            value={body}
+            onChange={(event) => setBody(event.target.value)}
+            style={{ minHeight: 360, resize: "vertical" }}
+          />
+        </div>
+
+        <div style={{ display: "flex", justifyContent: "flex-end" }}>
+          <button
+            type="submit"
+            disabled={isSaving}
+            style={{
+              border: "none",
+              borderRadius: "var(--ml-radius-md)",
+              padding: "10px 14px",
+              background: "var(--ml-accent-primary)",
+              color: "var(--ml-text-primary)",
+              fontWeight: 600,
+            }}
+          >
+            {isSaving ? "Saving…" : "Save note"}
+          </button>
+        </div>
+      </form>
     </section>
   );
 }

web/src/lib/notes-client.ts

@@ -246,6 +246,24 @@ export async function listNotesForWorkspace(workspaceId: string): Promise<NoteSu
   return response.items.map(toNoteSummary);
 }
 
+export async function updateNoteDetail(
+  noteId: string,
+  workspaceId: string,
+  updates: {
+    title?: string;
+    body?: string;
+  },
+): Promise<void> {
+  const api = createNotesApiClient();
+  await api.fetch(
+    `/notes/${encodeURIComponent(noteId)}?workspaceId=${encodeURIComponent(workspaceId)}`,
+    {
+      method: "PATCH",
+      body: JSON.stringify(updates),
+    },
+  );
+}
+
 export async function getNoteDetail(noteId: string): Promise<NoteDetail | null> {
   const api = createNotesApiClient();
   const [workspaceResponse, noteResponse] = await Promise.all([