## 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
## What changed
Add `codex-runtime-agent-instance` with serializable registration requests and deserializable responses. Requests support OAuth, personal access tokens, and platform API keys, along with an installation ID, public key, harness metadata, and runtime role. Responses include runtime and host IDs plus ChatGPT or platform actor context.
Use `RedactedString` for credentials to keep secrets out of debug output.
## Testing
Add tests covering request serialization for all three credential types, debug redaction, response decoding for both actor types, and rejection of responses missing required fields.
GitOrigin-RevId: f33bae734fdd1402144dee407e5b868f5eef1d37