feat: remove all ClickHouse dependencies from SaaS layer

- Delete log/ package (ClickHouseConfig, ContainerLogService, LogController)
- Delete observability/ package (AgentStatusService, AgentStatusController)
- Remove clickhouse-jdbc dependency from pom.xml
- Remove cameleer.clickhouse config section from application.yml
- Delete associated test files

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

src/main/resources/application.yml

@@ -56,8 +56,3 @@ cameleer:
     container-cpu-shares: ${CAMELEER_CONTAINER_CPU_SHARES:512}
     cameleer3-server-endpoint: ${CAMELEER3_SERVER_ENDPOINT:http://cameleer3-server:8081}
     domain: ${DOMAIN:localhost}
-  clickhouse:
-    enabled: ${CLICKHOUSE_ENABLED:true}
-    url: ${CLICKHOUSE_URL:jdbc:clickhouse://clickhouse:8123/cameleer}
-    username: ${CLICKHOUSE_USERNAME:default}
-    password: ${CLICKHOUSE_PASSWORD:}