feat: add client-side permission gating to all write-action UIs
Gate all mutating UI elements with useCanDo() permission checks:
- BudgetPanel (budget_edit), PackingListPanel (packing_edit)
- DayPlanSidebar, DayDetailPanel (day_edit)
- ReservationsPanel, ReservationModal (reservation_edit)
- CollabNotes, CollabPolls, CollabChat (collab_edit)
- FileManager (file_edit, file_delete, file_upload)
- PlaceFormModal, PlaceInspector, PlacesSidebar (place_edit, file_upload)
- TripFormModal (trip_edit, trip_cover_upload)
- DashboardPage (trip_edit, trip_cover_upload, trip_delete, trip_archive)
- TripMembersModal (member_manage, share_manage)
Also: fix redundant getTripOwnerId queries in trips.ts, remove dead
getTripOwnerId function, fix TripMembersModal grid when share hidden,
fix canRemove logic, guard TripListItem empty actions div.
5f71b85c06