## Why
Model catalog refreshes need to use the same registered actor and credential owner as model requests when runtime authentication is enabled.
## What changed
- Add `ProviderAuthContext` to carry credentials and optional runtime authentication into model providers and catalog clients.
- Select runtime authentication independently for inference and catalog destinations. Reject unsupported OpenAI origins while preserving provider authentication for other destinations.
- Include API organization and project selectors in runtime registration. Reuse registered runtimes across projects within an organization and replace them when the organization changes.
- Preserve transport restrictions and account bindings, and strip sensitive headers on cross-origin redirects.
- Apply the catalog timeout to authentication and fetching while allowing credential refresh and registration to finish safely.
## Testing
Add coverage for runtime-authenticated catalogs, provider isolation, resource selection, gateway authentication, cross-origin redirects, and timeout recovery that preserves registration and refreshed tokens.
GitOrigin-RevId: c14f1a02159031ea0af1f9b26ea890f8dca7d6ad