Fix QA findings: remove duplicate migration, formatting, static classNames

- Remove migration 054 (duplicate of 035 which already has all 3 indexes,
  including a superior partial index for starred events)
- Fix handleEventDidMount indentation and missing semicolons
- Replace eventClassNames arrow function with static UMBRA_EVENT_CLASSES array
- Correct misleading subquery comment in dashboard.py

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

backend/alembic/versions/054_add_calendar_event_indexes.py

@@ -1,36 +0,0 @@
-"""Add performance indexes to calendar_events
-
-Revision ID: 054
-Revises: 053
-"""
-from alembic import op
-
-revision = "054"
-down_revision = "053"
-
-
-def upgrade():
-    # Covers range queries in dashboard today's events and events list
-    op.create_index(
-        "ix_calendar_events_calendar_start",
-        "calendar_events",
-        ["calendar_id", "start_datetime"],
-    )
-    # Covers bulk DELETE on recurrence edit/regeneration and sibling lookups
-    op.create_index(
-        "ix_calendar_events_parent_event_id",
-        "calendar_events",
-        ["parent_event_id"],
-    )
-    # Covers starred widget query (calendar_id + is_starred + start_datetime)
-    op.create_index(
-        "ix_calendar_events_calendar_starred_start",
-        "calendar_events",
-        ["calendar_id", "is_starred", "start_datetime"],
-    )
-
-
-def downgrade():
-    op.drop_index("ix_calendar_events_calendar_starred_start", table_name="calendar_events")
-    op.drop_index("ix_calendar_events_parent_event_id", table_name="calendar_events")
-    op.drop_index("ix_calendar_events_calendar_start", table_name="calendar_events")

backend/app/routers/dashboard.py

@@ -35,8 +35,8 @@ async def get_dashboard(
     today = client_date or date.today()
     upcoming_cutoff = today + timedelta(days=current_settings.upcoming_days)
 
-    # Fetch calendar IDs once as a plain list — PostgreSQL handles IN (1,2,3) more
-    # efficiently than re-evaluating a correlated subquery for each of the 3 queries below.
+    # Fetch calendar IDs once as a plain list — avoids repeating the subquery
+    # expression in each of the 3+ queries below and makes intent clearer.
     calendar_id_result = await db.execute(
         select(Calendar.id).where(Calendar.user_id == current_user.id)
     )

frontend/src/components/calendar/CalendarPage.tsx

@@ -33,6 +33,8 @@ const viewLabels: Record<CalendarView, string> = {
   timeGridDay: 'Day',
 };
 
+const UMBRA_EVENT_CLASSES = ['umbra-event'];
+
 export default function CalendarPage() {
   const queryClient = useQueryClient();
   const location = useLocation();
@@ -551,7 +553,7 @@ export default function CalendarPage() {
         <span className="text-[10px] opacity-50 leading-tight tabular-nums">{arg.timeText}</span>
       </div>
     );
-  }, [])
+  }, []);
 
 
   return (
@@ -708,7 +710,7 @@ export default function CalendarPage() {
                 slotLabelFormat={{ hour: 'numeric', minute: '2-digit', meridiem: 'short' }}
                 slotEventOverlap={false}
                 eventDidMount={handleEventDidMount}
-                eventClassNames={() => ['umbra-event']}
+                eventClassNames={UMBRA_EVENT_CLASSES}
                 eventContent={renderEventContent}
               />
             </div>