Fix Docker socket permission issue in CI/CD workflow

- Add --privileged flag and explicit Docker socket mount to container
- Configure Buildx to use 'docker' driver instead of 'docker-container'
- This avoids nested container permission issues while using full Ubuntu image

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

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

.gitea/workflows/build-deploy.yml

@@ -10,6 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     container:
       image: ghcr.io/catthehacker/ubuntu:full-22.04
+      options: --privileged -v /var/run/docker.sock:/var/run/docker.sock
 
     steps:
       - name: Checkout code
@@ -24,6 +25,8 @@ jobs:
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
+        with:
+          driver: docker
 
       - name: Build and push Docker image
         uses: docker/build-push-action@v6