feat: deposit deductions, booking payments persistence, minibar in release form

- Migrations 061 (booking_payments) + 062 (deposit_deduction_presets)
- Backend: booking payments CRUD (GET/POST/DELETE), auto-updates paid_amount on booking
- Backend: deposit deduction presets CRUD (GET/POST/PATCH/DELETE)
- Backend: GET /deposit/minibar endpoint returns minibar consumptions for booking
- Backend: release endpoint accepts items[] for itemized email to guest
- Frontend: payments loaded from API — persist across page reloads
- Frontend: deposit release form redesigned — preset buttons, minibar auto-fill, itemized list
- Frontend: onFocus select on all amount inputs (no more manual "0" removal)

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

backend/migrations/061_booking_payments.sql

@@ -0,0 +1,11 @@
+CREATE TABLE booking_payments (
+  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  hotel_id UUID NOT NULL REFERENCES hotels(id),
+  booking_id UUID NOT NULL REFERENCES bookings(id) ON DELETE CASCADE,
+  amount NUMERIC(10,2) NOT NULL,
+  method TEXT NOT NULL DEFAULT 'cash',
+  note TEXT,
+  created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+  created_by UUID REFERENCES users(id)
+);
+CREATE INDEX ON booking_payments(booking_id);