fix(ci): use hardcoded registry URL without https prefix

Docker login requires registry URL without protocol prefix.

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

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

.gitea/workflows/release.yml

@@ -29,7 +29,7 @@ jobs:
       - name: Login to Gitea Container Registry
         uses: docker/login-action@v3
         with:
-          registry: ${{ github.server_url }}
+          registry: tea.millaguie.net
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}