fix(superset): stabilize bootstrap after clean reset

- make superset-init run via dedicated init service\n- tolerate missing dm views during early metadata refresh\n- add clickhouse dependency for init service\n- document clean-reset behavior and re-init flow

docker-compose.yml

@@ -180,6 +180,8 @@ services:
     depends_on:
       postgres-metadata:
         condition: service_healthy
+      clickhouse:
+        condition: service_started
 
   prometheus:
     image: prom/prometheus:v2.53.4