fix: Add contents write permission for release job

GitHub Actions requires explicit permissions to create releases.
Added permissions.contents: write to the release job.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.github/workflows/release.yml

@@ -58,6 +58,8 @@ jobs:
   release:
     needs: build
     runs-on: ubuntu-latest
+    permissions:
+      contents: write
 
     steps:
     - name: Checkout code