Records the shipped identity and invalidation contract for the /api/models
catalog cache in api/config.py — what is cached (in-memory snapshot, per-profile
models_cache.json, cold vs hot path), the three source axes and why each is
fingerprinted the way it is, and the one-directional deny-list invariant for the
volatile-key sets. Changes no runtime behavior; added after #7556 shipped, whose
review flagged the contract as undocumented.
Verified before merge: all 14 symbols the doc names exist in api/config.py
(_available_models_cache, _AVAILABLE_MODELS_CACHE_TTL, _get_models_cache_path,
_models_cache_provenance, _sync_models_cache_provenance,
_models_cache_source_fingerprint, _is_loadable_disk_cache,
_models_cache_file_fingerprint, _auth_store_semantic_fingerprint,
_AUTH_FINGERPRINT_VOLATILE_KEYS, _codex_models_cache_fingerprint,
_CODEX_CACHE_FINGERPRINT_VOLATILE_KEYS, _endpoint_advertised_model_ids), and the
cited test_unknown_codex_field_stays_in_fingerprint is real
(tests/test_issue7540_codex_catalog_fingerprint.py:287). docs/architecture/ is
allowlisted in .gitignore with both the dir and /** lines, so the new file is
genuinely trackable.
Co-authored-by: webtecnica <webtecnica@users.noreply.github.com>
