Centralize thread MCP state in McpRuntime (#34930)

## What changed

- Make `McpRuntime` own the published MCP configuration, connections, elicitation routing, and selected capability roots for a thread.
- Capture immutable MCP bindings for model steps and tool calls so in-flight work keeps a consistent connection set and approval authority while refreshed state is published atomically.
- Mark MCP state dirty when relevant configuration, plugins, environments, authentication, or elicitation capabilities change, then rebuild it before the next sampling request or out-of-band MCP operation.
- Separate config reloads from server invalidation: `ReloadMcpConfig` applies resolved MCP inputs, while `RefreshMcpServers` requests reinitialization from the thread's latest state.

## Testing

- Cover refreshed state visibility for existing turns, stable step bindings, current approval authority, cancelled refresh retries, resource-client reconciliation, and Apps recovery between sampling requests.

GitOrigin-RevId: 59eabb1aa8dc083426bd18ef4d3630508f376401

codex-rs/codex-mcp/src/lib.rs

@@ -1,9 +1,7 @@
 pub use binding::McpBinding;
 pub use binding::PreparedMcpCall;
-pub use connection_manager::McpConnectionSet;
 pub use connection_manager::tool_is_model_visible;
 pub use elicitation::ElicitationLifecycle;
-pub use elicitation::ElicitationRequestRouter;
 pub use elicitation::ElicitationReviewRequest;
 pub use elicitation::ElicitationReviewer;
 pub use elicitation::ElicitationReviewerHandle;
@@ -14,13 +12,11 @@ pub use resource_client::McpResourceReadResult;
 pub use rmcp_client::MCP_SANDBOX_STATE_META_CAPABILITY;
 pub use runtime::McpRuntime;
 pub use runtime::McpRuntimeContext;
+pub use runtime::McpRuntimeInput;
 pub use runtime::SandboxState;
 pub use tool_catalog_cache::McpToolCatalogCache;
 pub use tools::ToolInfo;
 
-/// Backward-compatible name for the MCP connection set.
-pub type McpConnectionManager = McpConnectionSet;
-
 /// Backward-compatible name for the shared Codex Apps tools runtime.
 pub type CodexAppsToolsCache = codex_connectors::ConnectorRuntimeManager<ToolInfo>;
 /// Backward-compatible name for the Codex Apps runtime context key.