Test fix on local

.gitea/workflows/ci.yml

@@ -14,6 +14,11 @@ on:
 jobs:
   backend:
     runs-on: ubuntu-latest
+    env:
+      # Kafka advertises this host on its EXTERNAL listener. The test process runs in
+      # a job container, so "localhost" (the compose default, correct for a dev box)
+      # would point the client at itself after bootstrap.
+      KAFKA_EXTERNAL_HOST: host.docker.internal
     steps:
       - uses: actions/checkout@v4
 
@@ -34,9 +39,11 @@ jobs:
       - name: Wait for Kafka
         run: |
           for i in $(seq 1 90); do
+            # Probe the INTERNAL listener: the EXTERNAL one advertises
+            # host.docker.internal, which does not resolve inside the broker container.
             if docker compose exec -T kafka \
               /opt/kafka/bin/kafka-broker-api-versions.sh \
-              --bootstrap-server localhost:9092 >/dev/null 2>&1; then
+              --bootstrap-server kafka:29092 >/dev/null 2>&1; then
               echo "Kafka is ready"
               exit 0
             fi