fix(ci): use GITHUB_TOKEN for container registry authentication

Use built-in GITHUB_TOKEN instead of custom secrets for Gitea container
registry login. This is more secure and doesn't require manual token
management.

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

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

.gitea/workflows/release.yml

@@ -29,9 +29,9 @@ jobs:
       - name: Login to Gitea Container Registry
         uses: docker/login-action@v3
         with:
-          registry: ${{ secrets.REGISTRY_URL }}
-          username: ${{ secrets.REGISTRY_USERNAME }}
-          password: ${{ secrets.REGISTRY_PASSWORD }}
+          registry: ${{ github.server_url }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Build and push backend image
         uses: docker/build-push-action@v5
@@ -43,8 +43,8 @@ jobs:
             BUILD_DATE=${{ steps.date.outputs.date }}
             GIT_COMMIT=${{ github.sha }}
           tags: |
-            ${{ secrets.REGISTRY_URL }}/trenes/backend:${{ steps.version.outputs.version }}
-            ${{ secrets.REGISTRY_URL }}/trenes/backend:latest
+            tea.millaguie.net/millaguie/trenes-backend:${{ steps.version.outputs.version }}
+            tea.millaguie.net/millaguie/trenes-backend:latest
           provenance: false
           sbom: false
 
@@ -60,17 +60,17 @@ jobs:
             BUILD_DATE=${{ steps.date.outputs.date }}
             GIT_COMMIT=${{ github.sha }}
           tags: |
-            ${{ secrets.REGISTRY_URL }}/trenes/frontend:${{ steps.version.outputs.version }}
-            ${{ secrets.REGISTRY_URL }}/trenes/frontend:latest
+            tea.millaguie.net/millaguie/trenes-frontend:${{ steps.version.outputs.version }}
+            tea.millaguie.net/millaguie/trenes-frontend:latest
           provenance: false
           sbom: false
 
       - name: Summary
         run: |
-          echo "### Docker Images Published 🐳" >> $GITHUB_STEP_SUMMARY
+          echo "### Docker Images Published" >> $GITHUB_STEP_SUMMARY
           echo "" >> $GITHUB_STEP_SUMMARY
           echo "**Version:** ${{ steps.version.outputs.version }}" >> $GITHUB_STEP_SUMMARY
           echo "" >> $GITHUB_STEP_SUMMARY
           echo "**Images:**" >> $GITHUB_STEP_SUMMARY
-          echo "- \`${{ secrets.REGISTRY_URL }}/trenes/backend:${{ steps.version.outputs.version }}\`" >> $GITHUB_STEP_SUMMARY
-          echo "- \`${{ secrets.REGISTRY_URL }}/trenes/frontend:${{ steps.version.outputs.version }}\`" >> $GITHUB_STEP_SUMMARY
+          echo "- tea.millaguie.net/millaguie/trenes-backend:${{ steps.version.outputs.version }}" >> $GITHUB_STEP_SUMMARY
+          echo "- tea.millaguie.net/millaguie/trenes-frontend:${{ steps.version.outputs.version }}" >> $GITHUB_STEP_SUMMARY