fix(bookings): preserve accommodation dates when place is unlinked or missing

- Remove NOT NULL constraint on day_accommodations.place_id (migration)
  and change ON DELETE CASCADE → SET NULL so deleting a place no longer
  cascades to the accommodation row
- Switch listAccommodations / getAccommodationWithPlace to LEFT JOIN so
  accommodations without a linked place are visible to the modal
- Relax create/update guards in reservationService to only require
  start_day_id + end_day_id, not place_id; place_id remains optional
- Client save guard now sends create_accommodation whenever FROM/TO days
  are set, regardless of whether a hotel place was selected
- Add re-hydration useEffect in ReservationModal to back-fill hotel
  fields from the accommodations prop when it arrives after modal opens
  (race between isOpen and the tripAccommodations fetch)
- Fix demo-seed TDZ crash: move db Proxy declaration before DEMO_MODE
  block so circular require in demo-reset resolves correctly
- Sidebar accommodation badge falls back to reservation title when
  place_name is null; click/cursor disabled for placeless accommodations
- listAccommodations now joins reservations to expose reservation_title

server/src/db/schema.ts

@@ -344,7 +344,7 @@ function createTables(db: Database.Database): void {
     CREATE TABLE IF NOT EXISTS day_accommodations (
       id INTEGER PRIMARY KEY AUTOINCREMENT,
       trip_id INTEGER NOT NULL REFERENCES trips(id) ON DELETE CASCADE,
-      place_id INTEGER NOT NULL REFERENCES places(id) ON DELETE CASCADE,
+      place_id INTEGER REFERENCES places(id) ON DELETE SET NULL,
       start_day_id INTEGER NOT NULL REFERENCES days(id) ON DELETE CASCADE,
       end_day_id INTEGER NOT NULL REFERENCES days(id) ON DELETE CASCADE,
       check_in TEXT,