Expose disabled plugin settings in the app-server API (#44905)

## What changed

- Accept `disabledPluginIds` in `thread/settings/update` and `turn/start`. A supplied list replaces the saved selection; omission or `null` preserves it, and `[]` clears it.
- Return the selection in thread start, resume, and fork responses and `thread/settings/updated` notifications. Update generated schemas and client types.
- Restore disabled plugin IDs from the history retained at the requested fork boundary, preserving explicit overrides.

The selection persists across resume but does not yet filter plugin capabilities.

## Testing

Add coverage for replacing, preserving, and clearing selections without inference; turn-start notifications; resume; and fork boundaries across legacy and paginated history, with loaded and restarted parents. Add a core regression test for history restoration and explicit clearing.

GitOrigin-RevId: 654a8c2a0527228d422c0dd4919228447e2663db

codex-rs/app-server/src/message_processor_tracing_tests.rs

@@ -662,6 +662,7 @@ async fn turn_start_jsonrpc_span_parents_core_turn_spans() -> Result<()> {
             ClientRequest::TurnStart {
                 request_id: RequestId::Integer(3),
                 params: TurnStartParams {
+                    disabled_plugin_ids: None,
                     environments: None,
                     thread_id,
                     client_user_message_id: None,