feat(reservations): service + validators + exclusivity tests

Adds the berth_reservations service covering the full lifecycle
(pending -> active -> ended/cancelled) with tenant scoping, DB-enforced
exclusivity on the idx_br_active partial unique index, and
client-or-company-member cross-checks for yacht ownership.

- validators: createPending / activate / end / cancel / list schemas
- service: createPending, activate, endReservation, cancel, getById,
  listReservations — with narrow 23505/idx_br_active catch that
  re-queries the conflicting active reservation
- socket events: berth_reservation:{created,activated,ended,cancelled}
- tests: unit (lifecycle, tenant, membership cross-check),
  integration (concurrent-activate ConflictError + re-activate after end)

src/lib/validators/reservations.ts

@@ -0,0 +1,42 @@
+import { z } from 'zod';
+import { baseListQuerySchema } from '@/lib/api/route-helpers';
+
+export const RESERVATION_STATUSES = ['pending', 'active', 'ended', 'cancelled'] as const;
+export const TENURE_TYPES = ['permanent', 'fixed_term', 'seasonal'] as const;
+
+export const createPendingSchema = z.object({
+  berthId: z.string().min(1),
+  clientId: z.string().min(1),
+  yachtId: z.string().min(1),
+  interestId: z.string().optional(),
+  startDate: z.coerce.date(),
+  tenureType: z.enum(TENURE_TYPES).optional().default('permanent'),
+  notes: z.string().optional(),
+});
+
+export const activateSchema = z.object({
+  contractFileId: z.string().optional(),
+  effectiveDate: z.coerce.date().optional(),
+});
+
+export const endReservationSchema = z.object({
+  endDate: z.coerce.date(),
+  notes: z.string().optional(),
+});
+
+export const cancelSchema = z.object({
+  reason: z.string().optional(),
+});
+
+export const listReservationsSchema = baseListQuerySchema.extend({
+  status: z.enum(RESERVATION_STATUSES).optional(),
+  berthId: z.string().optional(),
+  clientId: z.string().optional(),
+  yachtId: z.string().optional(),
+});
+
+export type CreatePendingInput = z.infer<typeof createPendingSchema>;
+export type ActivateInput = z.infer<typeof activateSchema>;
+export type EndReservationInput = z.infer<typeof endReservationSchema>;
+export type CancelInput = z.infer<typeof cancelSchema>;
+export type ListReservationsInput = z.infer<typeof listReservationsSchema>;