Fix recurrence edit/delete scope and simplify weekly UI

- Weekly recurrence no longer requires manual weekday selection;
  auto-derives from event start date
- EventForm now receives and forwards editScope prop to API
  (edit_scope in PUT body, scope query param in DELETE)
- CalendarPage passes scope through proper prop instead of _editScope hack
- Backend this_and_future: inherits parent's recurrence_rule when child
  has none, properly regenerates children after edit
- Backend: parent-level edits now delete+regenerate all children

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

backend/app/routers/events.py

@@ -304,6 +304,13 @@ async def update_event(
         this_original_start = event.original_start or event.start_datetime
 
         if parent_id is not None:
+            # Fetch the parent's recurrence_rule before deleting siblings
+            parent_result = await db.execute(
+                select(CalendarEvent).where(CalendarEvent.id == parent_id)
+            )
+            parent_event = parent_result.scalar_one_or_none()
+            parent_rule = parent_event.recurrence_rule if parent_event else None
+
             await db.execute(
                 delete(CalendarEvent).where(
                     CalendarEvent.parent_event_id == parent_id,
@@ -318,17 +325,33 @@ async def update_event(
             event.is_recurring = True
             event.original_start = None
 
-            # If a new recurrence_rule was provided, regenerate children from this point
+            # Inherit parent's recurrence_rule if none was provided in update
+            if not event.recurrence_rule and parent_rule:
+                event.recurrence_rule = parent_rule
+
+            # Regenerate children from this point
             if event.recurrence_rule:
                 await db.flush()
                 children = generate_occurrences(event)
                 for child in children:
                     db.add(child)
         else:
-            # Not part of a series — plain update
+            # This IS a parent — update it and regenerate all children
             for key, value in update_data.items():
                 setattr(event, key, value)
 
+            # Delete all existing children and regenerate
+            if event.recurrence_rule:
+                await db.execute(
+                    delete(CalendarEvent).where(
+                        CalendarEvent.parent_event_id == event.id
+                    )
+                )
+                await db.flush()
+                children = generate_occurrences(event)
+                for child in children:
+                    db.add(child)
+
         await db.commit()
 
     else:

frontend/src/components/calendar/CalendarPage.tsx

@@ -46,6 +46,7 @@ export default function CalendarPage() {
   const [scopeDialogOpen, setScopeDialogOpen] = useState(false);
   const [scopeAction, setScopeAction] = useState<ScopeAction>('edit');
   const [scopeEvent, setScopeEvent] = useState<CalendarEvent | null>(null);
+  const [activeEditScope, setActiveEditScope] = useState<'this' | 'this_and_future' | null>(null);
 
   const { data: calendars = [] } = useCalendars();
 
@@ -177,8 +178,8 @@ export default function CalendarPage() {
   const handleScopeChoice = (scope: 'this' | 'this_and_future') => {
     if (!scopeEvent) return;
     if (scopeAction === 'edit') {
-      // For edits, open form — the form will send scope on save
-      setEditingEvent({ ...scopeEvent, _editScope: scope } as any);
+      setEditingEvent(scopeEvent);
+      setActiveEditScope(scope);
       setShowForm(true);
       setScopeDialogOpen(false);
     } else if (scopeAction === 'delete') {
@@ -235,6 +236,7 @@ export default function CalendarPage() {
     calendarRef.current?.getApi().unselect();
     setShowForm(false);
     setEditingEvent(null);
+    setActiveEditScope(null);
     setSelectedStart(null);
     setSelectedEnd(null);
     setSelectedAllDay(false);
@@ -323,6 +325,7 @@ export default function CalendarPage() {
           initialStart={selectedStart}
           initialEnd={selectedEnd}
           initialAllDay={selectedAllDay}
+          editScope={activeEditScope}
           onClose={handleCloseForm}
         />
       )}

frontend/src/components/calendar/EventForm.tsx

@@ -25,6 +25,7 @@ interface EventFormProps {
   initialStart?: string | null;
   initialEnd?: string | null;
   initialAllDay?: boolean;
+  editScope?: 'this' | 'this_and_future' | null;
   onClose: () => void;
 }
 
@@ -74,7 +75,7 @@ function parseRecurrenceRule(raw?: string): RecurrenceRule | null {
   }
 }
 
-export default function EventForm({ event, initialStart, initialEnd, initialAllDay, onClose }: EventFormProps) {
+export default function EventForm({ event, initialStart, initialEnd, initialAllDay, editScope, onClose }: EventFormProps) {
   const queryClient = useQueryClient();
   const { data: calendars = [] } = useCalendars();
   const isAllDay = event?.all_day ?? initialAllDay ?? false;
@@ -125,7 +126,8 @@ export default function EventForm({ event, initialStart, initialEnd, initialAllD
       case 'every_n_days':
         return { type: 'every_n_days', interval: recurrenceInterval };
       case 'weekly':
-        return { type: 'weekly', weekday: recurrenceWeekday };
+        // No weekday needed — backend derives it from the event's start date
+        return { type: 'weekly' };
       case 'monthly_nth_weekday':
         return { type: 'monthly_nth_weekday', week: recurrenceWeek, weekday: recurrenceWeekday };
       case 'monthly_date':
@@ -145,7 +147,7 @@ export default function EventForm({ event, initialStart, initialEnd, initialAllD
         endDt = adjustAllDayEndForSave(endDt);
       }
 
-      const payload = {
+      const payload: Record<string, any> = {
         title: data.title,
         description: data.description,
         start_datetime: data.start_datetime,
@@ -158,6 +160,9 @@ export default function EventForm({ event, initialStart, initialEnd, initialAllD
       };
 
       if (event) {
+        if (editScope) {
+          payload.edit_scope = editScope;
+        }
         const response = await api.put(`/events/${event.id}`, payload);
         return response.data;
       } else {
@@ -179,7 +184,8 @@ export default function EventForm({ event, initialStart, initialEnd, initialAllD
 
   const deleteMutation = useMutation({
     mutationFn: async () => {
-      await api.delete(`/events/${event?.id}`);
+      const params = editScope ? `?scope=${editScope}` : '';
+      await api.delete(`/events/${event?.id}${params}`);
     },
     onSuccess: () => {
       queryClient.invalidateQueries({ queryKey: ['calendar-events'] });
@@ -346,18 +352,9 @@ export default function EventForm({ event, initialStart, initialEnd, initialAllD
             )}
 
             {recurrenceType === 'weekly' && (
-              <div className="space-y-2">
-                <Label htmlFor="weekday">Day of week</Label>
-                <Select
-                  id="weekday"
-                  value={recurrenceWeekday.toString()}
-                  onChange={(e) => setRecurrenceWeekday(parseInt(e.target.value))}
-                >
-                  {WEEKDAYS.map((name, i) => (
-                    <option key={i} value={i}>{name}</option>
-                  ))}
-                </Select>
-              </div>
+              <p className="text-xs text-muted-foreground">
+                Repeats every week on the same day as the start date.
+              </p>
             )}
 
             {recurrenceType === 'monthly_nth_weekday' && (