Expose effective login methods in config requirements (#45495)

## Why

Configuration requirements did not report which login methods the running app server permits after applying managed policy, forced login settings, and workspace restrictions.

## What changed

- Add `allowedLoginMethods` to `configRequirements/read`, using the running authentication manager's effective policy rather than newly read authentication settings.
- Return requirements when login methods are restricted even without managed requirements, while preserving `requirements: null` for the unrestricted default.
- Update protocol schemas and generated TypeScript and Python types. An empty list permits no login method; older servers may omit the field.

## Testing

Add coverage for managed and forced login restrictions, workspace intersections, policy reporting after requirements files change, invalid login methods, and API-only Amazon Bedrock without ChatGPT requests. Extend tests for conflicting authentication requirements and cloud policy precedence.

GitOrigin-RevId: 56c0767a74143e793aac2ac165d0cbe98a09469b

codex-rs/app-server-protocol/src/protocol/v2/config.rs

@@ -412,6 +412,9 @@ pub struct ConfigRequirements {
     pub model_provider: Option<String>,
     /// Complete required provider definitions, using config.toml field names.
     pub model_providers: Option<HashMap<String, JsonValue>>,
+    /// Effective login methods after managed, forced-login, and workspace restrictions.
+    /// An empty list permits no login method. Older servers may omit this field.
+    pub allowed_login_methods: Option<Vec<ForcedLoginMethod>>,
     pub cli_auth_credentials_store: Option<CliAuthCredentialsStoreMode>,
     pub chatgpt_base_url: Option<String>,
     pub additional_developer_instructions: Option<String>,

codex-rs/app-server-protocol/src/protocol/v2/tests.rs

@@ -2120,6 +2120,7 @@ fn config_requirements_granular_allowed_approval_policy_is_marked_experimental()
         crate::experimental_api::ExperimentalApi::experimental_reason(&ConfigRequirements {
             model_provider: None,
             model_providers: None,
+            allowed_login_methods: None,
             application: None,
             cli_auth_credentials_store: None,
             chatgpt_base_url: None,