The Codex backend returns the per-account model catalog only when the
ChatGPT-Account-Id header is present. Without it, GET /backend-api/codex/models
responds 200 OK with {"models":[]} and the picker silently degrades to the
hardcoded fallback list — which is stale or wrong for the active plan
(no GPT-5.6 family, wrong context windows).
This was the upstream bug behind slow first responses and HTTP 520/120s SSE
hangs: Hermes was sending invalid slugs because the probe never saw them in
the catalog, and Codex's request builder also depends on the same JWT claim
that's now being threaded through both probe paths.
Fixes the probe-side paths in hermes_cli/codex_models.py and
agent/model_metadata.py by extracting chatgpt_account_id from the OAuth JWT
(mirroring the request-side logic already in auxiliary_client.py) and sending
it as a header.
Verified live:
- _fetch_models_from_api now returns the 10-model catalog (gpt-5.6-sol,
gpt-5.6-terra, gpt-5.6-luna, gpt-5.5, gpt-5.4, gpt-5.4-mini,
gpt-5.3-codex-spark, 3x -pro variants) instead of [].
- _fetch_codex_oauth_context_lengths resolves all 8 account models to 272K
context (matches direct API probes of the same account).
- end-to-end: hermes chat -m gpt-5.6-sol -q 'Reply with one word: pong'
returns 'pong' cleanly via the openai-codex route.
Same class of bug as PR #64760.
