feat(01-02): add withCount for notes and comprehensive tests

- AdminMemberController index() now includes withCount('notes')
- Created MemberNoteTest with 7 feature tests
- Tests cover: creation, retrieval, validation, audit logging, authorization, N+1 prevention, ordering
- All new tests passing (7/7)
- No regressions in existing test suite

app/Http/Controllers/AdminMemberController.php

@@ -15,7 +15,7 @@ class AdminMemberController extends Controller
 {
     public function index(Request $request)
     {
-        $query = Member::query()->with('user');
+        $query = Member::query()->with('user')->withCount('notes');
 
         // Text search (name, email, phone, Line ID, national ID)
         if ($search = $request->string('search')->toString()) {