Health check API (no API key needed, same host as this page)

…

• GET …/health → 200 while the API can answer: status = ok (H100) or degraded (backup only); 503 when both backends are down
• GET …/health/h100 → 200 only while the reserved H100 LLM engine is healthy, else 503
• GET …/health/rag → 200 only while the H100 embedding + reranker engines and the full-corpus RAG index are healthy, else 503
• GET …/health/backup → 200 only while the TrueIDC backup stack is healthy, else 503
• GET …/status/api → this page's JSON (same contract as status.iapp.co.th)