{"ok":true,"message":"RAG Brain session backend is running","mode":"temporary 24h isolated sessions","endpoints":{"health":"GET /api/health","createSession":"POST /api/session/create","getSession":"GET /api/session/:sessionId","resetSession":"POST /api/session/:sessionId/reset","cleanupSessions":"POST /api/sessions/cleanup","upload":"POST /api/session/:sessionId/pdfs/upload","uploadAndBuild":"POST /api/session/:sessionId/pdfs/upload-and-build","build":"POST /api/session/:sessionId/knowledge/build","query":"POST /api/session/:sessionId/query"}}