fix(ci): release 워크플로에 contents: write 권한 추가

DMG asset 업로드 시 softprops/action-gh-release가
"Resource not accessible by integration" 오류로 실패. 기본 GITHUB_TOKEN에
release 수정 권한이 없어 발생.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.github/workflows/release.yml

@@ -4,6 +4,9 @@ on:
   release:
     types: [published]
 
+permissions:
+  contents: write
+
 jobs:
   build-and-release:
     runs-on: macos-latest