fix(types): add missing useEffect import and fix type mismatches

Fixes from tsc type checking:
- Re-added useEffect import to ClubCourtsTab (used in CourtFormModal)
- Updated mock courts data to include created_at/updated_at timestamps
- Fixed CourtError dependencies type to match CourtDependencies structure
  (slot_instances_future/booked instead of upcoming_bookings)

All court-related TypeScript errors resolved. Build succeeds.

src/app/[locale]/admin/clubs/[club_id]/tabs/ClubCourtsTab.tsx

@@ -1,6 +1,6 @@
 'use client';
 
-import { useState } from 'react';
+import { useState, useEffect } from 'react';
 import { Loader2, AlertCircle, Plus, Edit, Trash2, AlertTriangle, X } from 'lucide-react';
 import {
   createCourt,

src/lib/api/admin-clubs.ts

@@ -168,9 +168,24 @@ export const MOCK_CLUB_DETAIL: AdminClubDetail = {
     timezone: 'Europe/Zurich',
   },
   courts: [
-    { court_id: 1, name: 'Court 1' },
-    { court_id: 2, name: 'Court 2' },
-    { court_id: 3, name: 'Court 3' },
+    {
+      court_id: 1,
+      name: 'Court 1',
+      created_at: '2024-01-01T00:00:00Z',
+      updated_at: '2024-01-01T00:00:00Z',
+    },
+    {
+      court_id: 2,
+      name: 'Court 2',
+      created_at: '2024-01-01T00:00:00Z',
+      updated_at: '2024-01-01T00:00:00Z',
+    },
+    {
+      court_id: 3,
+      name: 'Court 3',
+      created_at: '2024-01-01T00:00:00Z',
+      updated_at: '2024-01-01T00:00:00Z',
+    },
   ],
   slot_definitions: [],
   upcoming_slots: [],

src/types/courts.ts

@@ -96,7 +96,8 @@ export interface CourtError {
   errors?: ValidationError[];
   dependencies?: {
     slot_definitions: number;
-    upcoming_bookings: number;
+    slot_instances_future: number;
+    slot_instances_booked: number;
   };
 }