feat(app-server): update remote control APIs for better UX (#22877)

## Why
To help improve `codex remote-control` CLI UX which I plan to do in a
followup, this PR adds `server-name` to the various remote control APIs:
- `remoteControl/enable`
- `remoteControl/disable`
- `remoteControl/status/changed`

Also, add a `remoteControl/status/read` API. This will be helpful in the
Codex App.

codex-rs/app-server-protocol/schema/json/v2/RemoteControlStatusChangedNotification.json

@@ -22,12 +22,16 @@
     "installationId": {
       "type": "string"
     },
+    "serverName": {
+      "type": "string"
+    },
     "status": {
       "$ref": "#/definitions/RemoteControlConnectionStatus"
     }
   },
   "required": [
     "installationId",
+    "serverName",
     "status"
   ],
   "title": "RemoteControlStatusChangedNotification",