detect_provider_for_model() silently remapped models to OpenRouter when
the direct provider's credentials weren't found via env vars. Three bugs:
1. Credential check only looked at env vars from PROVIDER_REGISTRY,
missing credential pool entries, auth store, and OAuth tokens
2. When env var check failed, silently returned ('openrouter', slug)
instead of the direct provider the model actually belongs to
3. Users with valid credentials via non-env-var mechanisms (pool,
OAuth, Claude Code tokens) got silently rerouted
Fix:
- Expand credential check to also query credential pool and auth store
- Always return the direct provider match regardless of credential
status -- let client init handle missing creds with a clear error
rather than silently routing through the wrong provider
Same philosophy as the provider-required fix: don't guess, don't
silently reroute, error clearly when something is missing.
Closes#10300
Teknium
f2f9d0c819