feat(notifications): emit at maintenance/turn/sync/reauth events

packages/backend/tests/unit/maintenance-thread.test.ts

@@ -14,6 +14,13 @@ const seedSpoon = async (t: ReturnType<typeof convexTest>) =>
       email: '[email protected]',
       name: 'Maintenance Thread Owner',
     });
+    // Disable email so the notification emit does not schedule the best-effort
+    // node email action, whose async logging would race test teardown.
+    await ctx.db.insert('notificationPreferences', {
+      userId: ownerId,
+      emailEnabled: false,
+      updatedAt: now,
+    });
     const spoonId = await ctx.db.insert('spoons', {
       ownerId,
       name: 'Maintenance Thread Spoon',