feat(01-02): create MemberNoteController and routes

- MemberNoteController with index() and store() methods
- StoreNoteRequest with Traditional Chinese validation messages
- Routes registered at admin.members.notes.index/store
- JSON responses for AJAX consumption in Phase 2
- DB::transaction wrapper with AuditLogger::log

app/Http/Controllers/Admin/MemberNoteController.php

@@ -0,0 +1,48 @@
+<?php
+
+namespace App\Http\Controllers\Admin;
+
+use App\Http\Controllers\Controller;
+use App\Http\Requests\StoreNoteRequest;
+use App\Models\Member;
+use App\Support\AuditLogger;
+use Illuminate\Support\Facades\DB;
+
+class MemberNoteController extends Controller
+{
+    /**
+     * Get all notes for a member
+     */
+    public function index(Member $member)
+    {
+        $notes = $member->notes()->with('author')->get();
+
+        return response()->json(['notes' => $notes]);
+    }
+
+    /**
+     * Store a new note for a member
+     */
+    public function store(StoreNoteRequest $request, Member $member)
+    {
+        $note = DB::transaction(function () use ($request, $member) {
+            $note = $member->notes()->create([
+                'content' => $request->content,
+                'author_user_id' => $request->user()->id,
+            ]);
+
+            AuditLogger::log('note.created', $note, [
+                'member_id' => $member->id,
+                'member_name' => $member->full_name,
+                'author' => $request->user()->name,
+            ]);
+
+            return $note;
+        });
+
+        return response()->json([
+            'note' => $note->load('author'),
+            'message' => '備忘錄已新增',
+        ], 201);
+    }
+}

app/Http/Requests/StoreNoteRequest.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace App\Http\Requests;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class StoreNoteRequest extends FormRequest
+{
+    /**
+     * Determine if the user is authorized to make this request.
+     */
+    public function authorize(): bool
+    {
+        // Authorization is handled by the admin middleware on the route group
+        return true;
+    }
+
+    /**
+     * Get the validation rules that apply to the request.
+     *
+     * @return array<string, \Illuminate\Contracts\Validation\ValidationRule|array<mixed>|string>
+     */
+    public function rules(): array
+    {
+        return [
+            'content' => ['required', 'string', 'min:1', 'max:65535'],
+        ];
+    }
+
+    /**
+     * Get custom messages for validator errors.
+     */
+    public function messages(): array
+    {
+        return [
+            'content.required' => '備忘錄內容為必填欄位',
+            'content.min' => '備忘錄內容不可為空白',
+            'content.max' => '備忘錄內容不可超過 65535 字元',
+        ];
+    }
+}