[app-server] Add a method to list experimental features. (#10721)

- [x] Add a method to list experimental features.

codex-rs/app-server-protocol/schema/json/ClientRequest.json

@@ -422,6 +422,27 @@
       ],
       "type": "object"
     },
+    "ExperimentalFeatureListParams": {
+      "properties": {
+        "cursor": {
+          "description": "Opaque pagination cursor returned by a previous call.",
+          "type": [
+            "string",
+            "null"
+          ]
+        },
+        "limit": {
+          "description": "Optional page size; defaults to a reasonable server-side value.",
+          "format": "uint32",
+          "minimum": 0.0,
+          "type": [
+            "integer",
+            "null"
+          ]
+        }
+      },
+      "type": "object"
+    },
     "FeedbackUploadParams": {
       "properties": {
         "classification": {
@@ -3562,6 +3583,30 @@
       "title": "Model/listRequest",
       "type": "object"
     },
+    {
+      "properties": {
+        "id": {
+          "$ref": "#/definitions/RequestId"
+        },
+        "method": {
+          "enum": [
+            "experimentalFeature/list"
+          ],
+          "title": "ExperimentalFeature/listRequestMethod",
+          "type": "string"
+        },
+        "params": {
+          "$ref": "#/definitions/ExperimentalFeatureListParams"
+        }
+      },
+      "required": [
+        "id",
+        "method",
+        "params"
+      ],
+      "title": "ExperimentalFeature/listRequest",
+      "type": "object"
+    },
     {
       "properties": {
         "id": {