Add audio variants to user input protocols (#33923)

## What changed

- Add remote and local audio variants to core and app-server user inputs, including generated JSON and TypeScript schemas.
- Preserve audio fields when converting app-server inputs and response content into thread items.
- Keep unsupported audio out of model requests, TUI rendering, text extraction, and truncated tool output, using explicit text placeholders where audio is submitted as a model input.

## Testing

- Cover app-server media conversion, unsupported-input placeholders, TUI omission, and tool-output truncation.

GitOrigin-RevId: 16152bf3af674575ce569764a8b472e032e7569d

codex-rs/tui/src/chatwidget/tests/app_server.rs

@@ -538,6 +538,43 @@ async fn live_app_server_user_message_item_completed_does_not_duplicate_rendered
     assert!(drain_insert_history(&mut rx).is_empty());
 }
 
+#[tokio::test]
+async fn live_app_server_user_message_omits_unsupported_media() {
+    let (mut chat, mut rx, _op_rx) = make_chatwidget_manual(/*model_override*/ None).await;
+
+    chat.handle_server_notification(
+        ServerNotification::ItemCompleted(ItemCompletedNotification {
+            thread_id: "thread-1".to_string(),
+            turn_id: "turn-1".to_string(),
+            completed_at_ms: 0,
+            item: AppServerThreadItem::UserMessage {
+                id: "user-1".to_string(),
+                client_id: None,
+                content: vec![
+                    AppServerUserInput::Text {
+                        text: "Please inspect the attachments.".to_string(),
+                        text_elements: Vec::new(),
+                    },
+                    AppServerUserInput::Audio {
+                        url: "https://example.com/one.wav".to_string(),
+                    },
+                    AppServerUserInput::LocalAudio {
+                        path: test_path_buf("/tmp/two.wav"),
+                    },
+                ],
+            },
+        }),
+        /*replay_kind*/ None,
+    );
+
+    let inserted = drain_insert_history(&mut rx);
+    assert_eq!(inserted.len(), 1);
+    assert_chatwidget_snapshot!(
+        "live_app_server_user_message_omits_unsupported_media",
+        lines_to_single_string(&inserted[0]),
+    );
+}
+
 #[tokio::test]
 async fn live_app_server_turn_completed_clears_working_status_after_answer_item() {
     let (mut chat, mut rx, _op_rx) = make_chatwidget_manual(/*model_override*/ None).await;