app-server: Replay pending item requests on thread/resume (#12560)

Replay pending client requests after `thread/resume` and emit resolved
notifications when those requests clear so approval/input UI state stays
in sync after reconnects and across subscribed clients.

Affected RPCs:
- `item/commandExecution/requestApproval`
- `item/fileChange/requestApproval`
- `item/tool/requestUserInput`

Motivation:
- Resumed clients need to see pending approval/input requests that were
already outstanding before the reconnect.
- Clients also need an explicit signal when a pending request resolves
or is cleared so stale UI can be removed on turn start, completion, or
interruption.

Implementation notes:
- Use pending client requests from `OutgoingMessageSender` in order to
replay them after `thread/resume` attaches the connection, using
original request ids.
- Emit `serverRequest/resolved` when pending requests are answered
or cleared by lifecycle cleanup.
- Update the app-server protocol schema, generated TypeScript bindings,
and README docs for the replay/resolution flow.

High-level test plan:
- Added automated coverage for replaying pending command execution and
file change approval requests on `thread/resume`.
- Added automated coverage for resolved notifications in command
approval, file change approval, request_user_input, turn start, and turn
interrupt flows.
- Verified schema/docs updates in the relevant protocol and app-server
tests.

Manual testing:
- Tested reconnect/resume with multiple connections.
- Confirmed state stayed in sync between connections.

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

@@ -0,0 +1,42 @@
+use codex_app_server_protocol::JSONRPCErrorError;
+
+pub(crate) const TURN_TRANSITION_PENDING_REQUEST_ERROR_REASON: &str = "turnTransition";
+
+pub(crate) fn is_turn_transition_server_request_error(error: &JSONRPCErrorError) -> bool {
+    error
+        .data
+        .as_ref()
+        .and_then(|data| data.get("reason"))
+        .and_then(serde_json::Value::as_str)
+        == Some(TURN_TRANSITION_PENDING_REQUEST_ERROR_REASON)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::is_turn_transition_server_request_error;
+    use codex_app_server_protocol::JSONRPCErrorError;
+    use pretty_assertions::assert_eq;
+    use serde_json::json;
+
+    #[test]
+    fn turn_transition_error_is_detected() {
+        let error = JSONRPCErrorError {
+            code: -1,
+            message: "client request resolved because the turn state was changed".to_string(),
+            data: Some(json!({ "reason": "turnTransition" })),
+        };
+
+        assert_eq!(is_turn_transition_server_request_error(&error), true);
+    }
+
+    #[test]
+    fn unrelated_error_is_not_detected() {
+        let error = JSONRPCErrorError {
+            code: -1,
+            message: "boom".to_string(),
+            data: Some(json!({ "reason": "other" })),
+        };
+
+        assert_eq!(is_turn_transition_server_request_error(&error), false);
+    }
+}