fix(GRO-1633): add buildx network=host and provenance:false to web CI

GRO-1672 follow-up: mirror groombook/api CI fixes in groombook/web
- docker/setup-buildx-action: driver-opts network=host (DinD DNS fix)
- docker/build-push-action: provenance: false (registry push compat)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -78,6 +78,8 @@ jobs:
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
+        with:
+          driver-opts: network=host
 
       - name: Log in to Gitea Container Registry
         uses: docker/login-action@v3
@@ -92,6 +94,7 @@ jobs:
           context: .
           file: Dockerfile
           push: true
+          provenance: false
           tags: |
             git.farh.net/groombook/web:${{ steps.version.outputs.tag }}
             ${{ github.ref == 'refs/heads/main' && 'git.farh.net/groombook/web:latest' || '' }}