ci: use buildx with OCI label for auto repo linking

.gitea/workflows/ci.yml

@@ -14,8 +14,11 @@ jobs:
       - name: Login to Gitea Registry
         run: echo "${{ secrets.REGISTRY_TOKEN }}" | docker login gitea.chatgqt.top -u ${{ gitea.actor }} --password-stdin
 
-      - name: Build Docker Image
-        run: docker build -t gitea.chatgqt.top/gqt/test-ci:latest .
-
-      - name: Push Docker Image
-        run: docker push gitea.chatgqt.top/gqt/test-ci:latest
+      - name: Build and Push
+        run: |
+          docker buildx create --use --name gitea-builder 2>/dev/null || true
+          docker buildx build --push \
+            --provenance=false \
+            --tag gitea.chatgqt.top/gqt/test-ci:latest \
+            --label "org.opencontainers.image.source=https://gitea.chatgqt.top/gqt/test-ci" \
+            .