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-protocol/schema/json/ServerNotification.json

@@ -5895,6 +5895,14 @@
         "cwd": {
           "$ref": "#/definitions/AbsolutePathBuf"
         },
+        "disabledPluginIds": {
+          "default": [],
+          "description": "Saved list of disabled plugin IDs. Does not yet filter plugin capabilities.",
+          "items": {
+            "type": "string"
+          },
+          "type": "array"
+        },
         "effort": {
           "anyOf": [
             {