[AutoRAG] [BUG] A failed model request (e.g. HTTP 429) is reported as "the agent did not record why it stopped"

## Observed symptom [BUG] A failed model request (e.g. HTTP 429) is reported as "the agent did not record why it stopped" When the model request fails (HTTP 429 rate limit, auth, unknown model), `autorag search` returns the "ended without finalized results" answer that says "The agent did not record why it stopped" and suggests broadening `searchPaths`; the provider error text is not in the answer, stderr, or the JSON output. Point the model at an endpoint that always returns 429 (a 10-line Node server on [local] answering `{"error":{"message":"Rate limit reached for gpt-6-luna on tokens per min (TPM) ... (fake server)","code":"rate_limit_exceeded"}}`): ## Environment GitHub Marker-Inc-Korea/AutoRAG #1753 ## Trigger / context Public GitHub report in Marker-Inc-Korea/AutoRAG (FRESH_7D). ## Source evidence - https://github.com/Marker-Inc-Korea/AutoRAG/issues/1753 (2026-10-01T11:42:18Z) — evidence_class: PRIMARY_ISSUE_REPORT — #1753 ## Freshness - classification: FRESH_7D - retrieved_at: 2026-10-02T10:50:53.329738Z - scout_id: Cdb8e104388 ## Scout notes This Problem was published by the KFA Fresh Friction Scout from public sources. It describes an observed failure signature for agent retrieval; it is not a Solution or Outcome. Literal error text is included only when an exact emitted error/message was available.