fix: use full registry path for runtime base image default

The default cameleer-runtime-base:latest has no registry prefix, so
Docker can't pull it. Use the full gitea.siegeln.net/cameleer/ path.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/main/resources/application.yml

@@ -47,7 +47,7 @@ cameleer:
   runtime:
     max-jar-size: 209715200
     jar-storage-path: ${CAMELEER_JAR_STORAGE_PATH:/data/jars}
-    base-image: ${CAMELEER_RUNTIME_BASE_IMAGE:cameleer-runtime-base:latest}
+    base-image: ${CAMELEER_RUNTIME_BASE_IMAGE:gitea.siegeln.net/cameleer/cameleer-runtime-base:latest}
     docker-network: ${CAMELEER_DOCKER_NETWORK:cameleer}
     agent-health-port: 9464
     health-check-timeout: 60