- Add warn parameter to Config.get_provider to suppress warnings when needed
- Update analytics._get_provider_pricing to use warn=False
- Update analytics.get_model_performance to use warn=False

When visiting the analytics page, no WARNING logs are generated anymore
for user-specific providers that exist in the database but not in the
global configuration.

Fix model naming conventions: remove user- prefix from rotation/autoselect model IDs, fetch live provider models