fix: preserve local-only notes during loadNotes merge

mergeNotesByVersion only iterated incoming notes, dropping any
local-only notes (e.g. just created but not yet in the server/IDB
response). This caused note cards to disappear briefly after creation
when loadNotes raced with createNote.

Also rename E2E test note title to avoid name collision with existing
"Groceries" test.

https://claude.ai/code/session_01TdPpATUkmdY7DhBkmqrvWs

src/lib/stores/notes.test.ts

@@ -67,6 +67,17 @@ describe('mergeNotesByVersion', () => {
 		expect(result[0].id).toBe('n2');
 	});
 
+	it('preserves local-only notes not present in the incoming data', () => {
+		const localOnly = makeNote({ id: 'n1', version: 1, content: 'just created' });
+		const serverNote = makeNote({ id: 'n2', version: 1, content: 'from server' });
+
+		const result = mergeNotesByVersion([localOnly], [serverNote]);
+
+		expect(result).toHaveLength(2);
+		expect(result.find((n) => n.id === 'n1')?.content).toBe('just created');
+		expect(result.find((n) => n.id === 'n2')?.content).toBe('from server');
+	});
+
 	it('preserves multiple notes correctly during a race condition', () => {
 		const localNotes = [
 			makeNote({ id: 'n1', version: 5, content: '- [x] Just saved' }),

src/lib/stores/notes.ts

@@ -60,11 +60,19 @@ function isNetworkError(err: unknown): boolean {
  */
 export function mergeNotesByVersion(current: Note[], incoming: Note[]): Note[] {
 	const currentMap = new Map(current.map((n) => [n.id, n]));
+	const incomingIds = new Set<string>();
 	const merged = incoming.map((incomingNote) => {
+		incomingIds.add(incomingNote.id);
 		const local = currentMap.get(incomingNote.id);
 		if (local && local.version > incomingNote.version) return local;
 		return incomingNote;
 	});
+	// Preserve local-only notes (e.g. just created, not yet in server/IDB response)
+	for (const local of current) {
+		if (!incomingIds.has(local.id)) {
+			merged.push(local);
+		}
+	}
 	return merged;
 }