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)

tests/unit/validators.test.ts

@@ -8,6 +8,7 @@ import { createFieldSchema, updateFieldSchema } from '@/lib/validators/custom-fi
 import { createYachtSchema, transferOwnershipSchema } from '@/lib/validators/yachts';
 import { createCompanySchema } from '@/lib/validators/companies';
 import { addMembershipSchema } from '@/lib/validators/company-memberships';
+import { createPendingSchema } from '@/lib/validators/reservations';
 
 // ─── Client schemas ───────────────────────────────────────────────────────────
 
@@ -483,3 +484,49 @@ describe('addMembershipSchema', () => {
     expect(result.success).toBe(true);
   });
 });
+
+// ─── Reservation schemas ─────────────────────────────────────────────────────
+
+describe('createPendingSchema', () => {
+  const validInput = {
+    berthId: 'berth-1',
+    clientId: 'client-1',
+    yachtId: 'yacht-1',
+    startDate: '2026-05-01',
+  };
+
+  it('rejects missing berthId', () => {
+    const result = createPendingSchema.safeParse({
+      clientId: validInput.clientId,
+      yachtId: validInput.yachtId,
+      startDate: validInput.startDate,
+    });
+    expect(result.success).toBe(false);
+  });
+
+  it('rejects missing clientId', () => {
+    const result = createPendingSchema.safeParse({
+      berthId: validInput.berthId,
+      yachtId: validInput.yachtId,
+      startDate: validInput.startDate,
+    });
+    expect(result.success).toBe(false);
+  });
+
+  it('rejects missing yachtId', () => {
+    const result = createPendingSchema.safeParse({
+      berthId: validInput.berthId,
+      clientId: validInput.clientId,
+      startDate: validInput.startDate,
+    });
+    expect(result.success).toBe(false);
+  });
+
+  it('accepts minimal valid input with default tenureType', () => {
+    const result = createPendingSchema.safeParse(validInput);
+    expect(result.success).toBe(true);
+    if (result.success) {
+      expect(result.data.tenureType).toBe('permanent');
+    }
+  });
+});