Previous lazy-import fix still required langchain at function call time.
Root cause: langchain_openai/langchain_core are only in requirements-agent.txt,
not requirements-backend.txt. The /api/agent/llm-status endpoint runs in
the backend container which has 'openai' but not 'langchain'.
Rewrite _check_llm_provider_health() to use:
- AsyncOpenAI from 'openai' package (in both containers)
- httpx to call /api/agent/llm-config on localhost (same as agent does)
- system_ssl_context() for SSL (same as LLM test endpoint)
- openai exceptions (APIConnectionError, APITimeoutError, etc.)
No langchain dependency at all — works in both backend and agent containers.
Verified: 977 tests passed, import without langchain succeeds.
busya
ce368429f7