feat: implement Presentation layer for GET /api/v1/user/me / ログイン中ユーザー取得APIのPresentation層実装

[zigzagdev]

Motivation / 目的

AuthController::login のレスポンスはトークンのみでユーザーのidを返さないため、フロントエンドはログイン後に「自分自身」の情報を取得する手段を持っていなかった（#542）。これがマイページ表示ができない一因だった。

The login response only returns a token, never the user's id, so the frontend had no way to fetch "its own" user data after logging in (#542). This was one of the causes preventing mypage from displaying.

Domain層・Infra層は既存の findById をそのまま利用でき、Application層も既存の GetUserByIdUseCase をそのまま流用できるため、変更が必要だったのはPresentation層のみ。

Domain and Infra layers already have findById implemented, and the Application layer can reuse the existing GetUserByIdUseCase as-is, so only the Presentation layer required changes.

Closes #542

What I have done / 実施内容

• routes/api.php に GET /v1/user/me を auth:sanctum ミドルウェア付きで追加
• AuthController::me を追加し、$request->user()->id（Sanctumが認証セッション/トークンから解決した現在のユーザーのid）を既存の GetUserByIdUseCase に渡して結果を返す
• 既存の UserViewModelFactory / UserViewModel をそのまま再利用してレスポンスを整形

Test Results / テスト結果

• test_me_returns_200_with_authenticated_user_when_authenticated
• test_me_returns_401_when_unauthenticated
• test_me_returns_500_on_unexpected_error
• 既存の LoginTest / LogoutTest も回帰なしを確認済み

[zigzagdev]

Ok

[codecov]

Codecov Report

❌ Patch coverage is 94.80519% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 62.51%. Comparing base (0ea56e1) to head (9489ee7).

Files with missing lines	Patch %	Lines
...pp/Packages/Features/Controller/AuthController.php	80.00%	4 Missing ⚠️

Additional details and impacted files

@@                  Coverage Diff                   @@
##             feat-user-me-api     #543      +/-   ##
======================================================
+ Coverage               62.21%   62.51%   +0.30%     
- Complexity               1604     1615      +11     
======================================================
  Files                     135      136       +1     
  Lines                    8252     8329      +77     
======================================================
+ Hits                     5134     5207      +73     
- Misses                   3118     3122       +4     

Files with missing lines	Coverage Δ
src/app/Packages/Features/Tests/MeTest.php	100.00% <100.00%> (ø)
...pp/Packages/Features/Controller/AuthController.php	93.22% <80.00%> (-6.78%)	⬇️

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