* fix(#3718): /api/models/live probes upstream for custom providers with model config (#3719)
@DanielMaly. Config model IDs were added to the ids list before the 'if not ids:' guard,
so a custom provider with a model: field skipped the live /v1/models probe and Settings'
refresh returned only the config entry. Now collects config IDs separately, always probes
for custom providers, merges live (priority) + config (fallback). Includes the maintainer
review follow-ups (CUSTOM_MODELS_ENDPOINT_TIMEOUT_SECONDS constant + behavioral tests).
Captured all 3 logical PR commits' net effect; routes.py + test verified byte-identical
to the PR head. + CHANGELOG v0.51.298.
* test(#3718): remove unused BytesIO import (ruff F401)
* test(#3719): update timeout assertion to CUSTOM_MODELS_ENDPOINT_TIMEOUT_SECONDS
The #3719 maintainer-review commit replaced the hardcoded urlopen timeout=8 with the
CUSTOM_MODELS_ENDPOINT_TIMEOUT_SECONDS constant (5.0). test_named_custom_live_fetch_uses_matching_entry_endpoint
asserted the old literal 8. Reference the constant directly now so the assertion can't
drift again. Not a behavior change — only the live-probe timeout value (8s -> 5s) moved,
URL + auth unchanged.
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Co-authored-by: nesquena-hermes <[email protected]>
