- Give cached_fetch_api_models the same stale-while-revalidate tier as
cached_provider_model_ids: TTL-expired entries within the 7d window are
served instantly while a background refresh rewrites the cache —
without this, every /model open an hour into the session re-blocked on
the live probe (#72762's stall class, deferred).
- Generalize _spawn_swr_refresh(cache_key, refresh_fn) so non-slug
custom:<base_url> keys reuse the same inflight-dedupe scaffolding;
slug behavior unchanged (default refresh_fn preserved).
- Convert the missed sibling site: acp_adapter/server.py
_named_custom_provider_catalogs() live-probed every custom_providers
row's /v1/models per ACP catalog build.
- Extract _cache_entry_valid() (the fp/models predicate existed 4x) and
validate 'at' is numeric so hand-edited/corrupt cache JSON degrades to
a live fetch instead of raising through the picker's blanket except.
- Flatten the dead api_mode conditional (fetch_api_models declares
api_mode=None; branch was behaviorally inert).
- Tests: 4 new guards (stale-serve, stale-window cutoff, generalized SWR
write-through, corrupt-at degradation) — stale-serve and corrupt-at
mutation-checked; 2 existing tests updated for the new behavior.
7cf71c32bb