Custom providers defined in config.yaml under were
completely invisible to the /model command in both gateway (Telegram,
Discord, etc.) and CLI. The provider listing skipped them and explicit
switching via --provider failed with "Unknown provider".
Root cause: gateway/run.py, cli.py, and model_switch.py only read the
dict from config, ignoring entirely.
Changes:
- providers.py: add resolve_custom_provider() and extend
resolve_provider_full() to check custom_providers after user_providers
- model_switch.py: propagate custom_providers through switch_model(),
list_authenticated_providers(), and get_authenticated_provider_slugs();
add custom provider section to provider listings
- gateway/run.py: read custom_providers from config, pass to all
model-switch calls
- cli.py: hoist config loading, pass custom_providers to listing and
switch calls
Tests: 4 new regression tests covering listing, resolution, and gateway
command handler. All 71 tests pass.