fix(airflow): set scheduler hostname for log server resolution

The scheduler's log server binds to [::]:8793 but doesn't advertise a
hostname, so the api-server gets 'http://:8793/...' (no host) when
fetching task logs. Fix by setting the scheduler's hostname and
configuring WORKER_LOG_SERVER_HOST so the api-server can reach it.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docker-compose.portainer.yml

@@ -198,6 +198,8 @@ services:
       AIRFLOW__CORE__LOAD_EXAMPLES: "false"
       AIRFLOW__CORE__SIMPLE_AUTH_MANAGER_USERS: "${AIRFLOW_ADMIN_USER:-admin}:admin"
       AIRFLOW__LOGGING__BASE_LOG_FOLDER: /opt/airflow/logs
+      AIRFLOW__LOGGING__WORKER_LOG_SERVER_HOST: airflow-scheduler
+      AIRFLOW__LOGGING__WORKER_LOG_SERVER_PORT: "8793"
       PG_HOST: sc_database
       PG_PORT: "5432"
       PG_USER: ${DB_USERNAME}
@@ -232,6 +234,8 @@ services:
       AIRFLOW__CORE__LOAD_EXAMPLES: "false"
       AIRFLOW__CORE__SIMPLE_AUTH_MANAGER_USERS: "${AIRFLOW_ADMIN_USER:-admin}:admin"
       AIRFLOW__LOGGING__BASE_LOG_FOLDER: /opt/airflow/logs
+      AIRFLOW__LOGGING__WORKER_LOG_SERVER_HOST: airflow-scheduler
+      AIRFLOW__LOGGING__WORKER_LOG_SERVER_PORT: "8793"
       PG_HOST: sc_database
       PG_PORT: "5432"
       PG_USER: ${DB_USERNAME}
@@ -247,6 +251,7 @@ services:
     networks:
       - backend
     restart: unless-stopped
+    hostname: airflow-scheduler
 
   # ── Airflow DB Init (one-shot) ───────────────────────────────────────
   airflow-init: