Implement dashboard composition (task 20)

- Add default_dashboard_layout jsonb to users + migration 0007
- Create _core/manifest.tsx with core.activity placeholder widget
- Register core manifest alongside calendar/lists/notes
- Update all three module manifests with real async server-component
  widget renders (upcoming events, month view, list items, notes)
- Add src/lib/dashboard.ts: computeDefaultLayout greedy packer +
  parseDashboardLayout Zod validator
- Build src/app/page.tsx: 12-col CSS Grid, static smColSpan lookup,
  per-widget Suspense for parallel loading, generic widget.render()
  dispatch — no widgetId branches
- Add tests/e2e/dashboard.spec.ts; all 4 E2E specs pass

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/modules/notes/manifest.tsx

@@ -1,12 +1,38 @@
-import type { ModuleManifest } from "../_core/module";
+import type { ModuleManifest, WidgetContext } from "../_core/module";
 import { z } from "zod";
-import { searchNotes } from "./server/queries";
+import { listWidgetNotes, searchNotes } from "./server/queries";
 
 const notesWidgetConfigSchema = z.object({
   filter: z.enum(["pinned", "all"]),
   limit: z.number().int().min(1).max(50).optional(),
 });
 
+async function NotesWidget({ config }: { config: unknown; ctx: WidgetContext }) {
+  const parsed = notesWidgetConfigSchema.parse(config);
+  const notes = await listWidgetNotes({ filter: parsed.filter, limit: parsed.limit ?? 5 });
+
+  if (notes.length === 0) {
+    return (
+      <p className="text-sm text-muted-foreground">
+        {parsed.filter === "pinned" ? "No pinned notes" : "No notes"}
+      </p>
+    );
+  }
+
+  return (
+    <ul className="space-y-2">
+      {notes.map((note) => (
+        <li key={note.id} className="space-y-0.5">
+          <p className="text-sm font-medium leading-snug">{note.title}</p>
+          {note.body && (
+            <p className="line-clamp-2 text-xs text-muted-foreground">{note.body}</p>
+          )}
+        </li>
+      ))}
+    </ul>
+  );
+}
+
 const manifest: ModuleManifest = {
   id: "notes",
   name: "Notes",
@@ -31,16 +57,9 @@ const manifest: ModuleManifest = {
       minSize: { w: 3, h: 2 },
       defaultPriority: 40,
       configSchema: notesWidgetConfigSchema,
-      defaultConfig: { filter: "pinned", limit: 10 },
+      defaultConfig: { filter: "pinned", limit: 5 },
       resolveConfigOptions: async () => undefined,
-      render: ({ config }) => {
-        const parsed = notesWidgetConfigSchema.parse(config);
-        return (
-          <div className="text-sm text-muted-foreground">
-            {parsed.filter === "pinned" ? "Pinned notes" : "Notes"}
-          </div>
-        );
-      },
+      render: (props) => <NotesWidget {...props} />,
     },
   ],
   quickAdds: [