Add an app-server API for reading app metadata (#33651)

## What changed

- Add the experimental `app/read` request for fetching metadata for up to 100
  app IDs, with optional display-only tool summaries.
- Preserve first-request order while deduplicating IDs, and report unknown or
  unauthorized apps as partial misses.
- Cache metadata by backend and ChatGPT account/workspace identity, refetch
  metadata-only entries when tools are requested, and preserve cached records
  when a backend request fails.

## Testing

- Cover request serialization, ordering, deduplication, partial misses, caching,
  tool-summary refetches, backend failures, cache isolation, and the ID limit.

GitOrigin-RevId: 55fc3281d99291e76d6c4a581e8d11569d3cb1ac

codex-rs/app-server-protocol/src/protocol/common.rs

@@ -735,6 +735,11 @@ client_request_definitions! {
         serialization: global("config"),
         response: v2::PluginShareDeleteResponse,
     },
+    AppsRead => "app/read" {
+        params: v2::AppsReadParams,
+        serialization: None,
+        response: v2::AppsReadResponse,
+    },
     AppsList => "app/list" {
         params: v2::AppsListParams,
         serialization: None,
@@ -3103,6 +3108,26 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn serialize_read_apps() -> Result<()> {
+        let request = ClientRequest::AppsRead {
+            request_id: RequestId::Integer(9),
+            params: v2::AppsReadParams {
+                app_ids: vec!["app-a".to_string(), "app-b".to_string()],
+                include_tools: true,
+            },
+        };
+        assert_eq!(
+            json!({
+                "method": "app/read",
+                "id": 9,
+                "params": { "appIds": ["app-a", "app-b"], "includeTools": true }
+            }),
+            serde_json::to_value(&request)?,
+        );
+        Ok(())
+    }
+
     #[test]
     fn serialize_environment_add() -> Result<()> {
         let request = ClientRequest::EnvironmentAdd {