fix: share job container network with Qdrant

docker run -d publishes ports to the Docker bridge network, but the
job container runs on a different Gitea Actions network. This causes
Connection refused when tests try http://localhost:6333.

Use --network container:$(hostname) so Qdrant shares the job container's
network stack, making localhost reachable.

.gitea/workflows/docker-build.yaml

@@ -30,7 +30,7 @@ jobs:
       - name: Start Qdrant
         run: |
           docker run -d --name qdrant \
-            -p 6333:6333 -p 6334:6334 \
+            --network "container:$(hostname)" \
             docker.io/qdrant/qdrant:latest
 
       - name: Wait for Qdrant