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

tests/e2e/checklist.spec.ts

@@ -62,10 +62,10 @@ test.describe('Checklist', () => {
 
 	test('Scenario: Multiple checked items persist after closing and reopening', async ({ authenticatedPage: page }) => {
 		// Given a checklist note with three items exists
-		await createChecklistNote(page, 'Groceries', ['Milk', 'Eggs', 'Bread']);
+		await createChecklistNote(page, 'Weekly Shop', ['Milk', 'Eggs', 'Bread']);
 
 		// When the user reopens and checks two items
-		await noteCard(page, 'Groceries').click();
+		await noteCard(page, 'Weekly Shop').click();
 		await page.getByTestId('checklist-checkbox').nth(0).click(); // Milk → done
 		await page.getByTestId('checklist-checkbox').nth(0).click(); // Eggs (now first) → done
 
@@ -74,7 +74,7 @@ test.describe('Checklist', () => {
 		await page.getByTestId('close-editor-btn').click();
 
 		// And the checked state persists after reopening
-		await noteCard(page, 'Groceries').click();
+		await noteCard(page, 'Weekly Shop').click();
 		await expect(page.getByTestId('checklist-toggle-done')).toContainText('2 done');
 		await expect(page.getByTestId('checklist-input')).toHaveCount(1); // Only Bread remains active
 		await expect(page.getByTestId('checklist-input').first()).toHaveValue('Bread');