Add availability checking and calendar sync to admin session editing:
**New Features:**
- Admin can now select time slots using visual picker with availability checking
- Time slot picker respects confirmed sessions and excludes current session from conflict check
- Calendar events are automatically updated when session time changes
- consulting_time_slots table is updated when time changes (old slots deleted, new slots created)
**New Component:**
- src/components/admin/TimeSlotPickerModal.tsx
- Reusable modal for time slot selection
- Shows visual grid of available time slots
- Range selection for multi-slot sessions
- Availability checking against consulting_sessions
- Supports editing (excludes current session from conflicts)
**Enhanced AdminConsulting.tsx:**
- Replaced simple time inputs with TimeSlotPickerModal
- Added state: timeSlotPickerOpen, editTotalBlocks, editTotalDuration
- Added handleTimeSlotSelect callback
- Enhanced saveMeetLink to:
- Update consulting_time_slots when time changes
- Call update-calendar-event edge function
- Update calendar event time via Google Calendar API
- Button shows selected time with duration and blocks count
**New Edge Function:**
- supabase/functions/update-calendar-event/index.ts
- Updates existing Google Calendar events when session time changes
- Uses PATCH method to update event (preserves event_id and history)
- Handles OAuth token refresh with caching
- Only updates start/end time (keeps title, description, meet link)
**Flow:**
1. Admin clicks "Edit" on session → Opens dialog
2. Admin clicks time button → Opens TimeSlotPickerModal
3. Admin selects new time → Only shows available slots
4. On save:
- consulting_sessions updated with new time
- Old consulting_time_slots deleted
- New consulting_time_slots created
- Google Calendar event updated (same event_id)
- Meet link preserved
**Benefits:**
- ✅ Prevents double-booking with availability checking
- ✅ Visual time slot selection (same UX as booking page)
- ✅ Calendar events stay in sync (no orphaned events)
- ✅ Time slots table properly maintained
- ✅ Meet link and event_id preserved during time changes
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
