Restore status header after stream recovery (#7660)

## Summary
- restore the previous status header when a non-error event arrives
after a stream retry
- add a regression test to ensure the reconnect banner clears once
streaming resumes

## Testing
- cargo fmt -- --config imports_granularity=Item
- cargo clippy --fix --all-features --tests --allow-dirty -p codex-tui
- NO_COLOR=0 cargo test -p codex-tui *(fails: vt100 color assertion
tests expect colored cells but the environment returns Default colors
even with NO_COLOR cleared and TERM/COLORTERM set)*

------
[Codex
Task](https://chatgpt.com/codex/tasks/task_i_69337f8c77508329b3ea85134d4a7ac7)

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

@@ -2905,6 +2905,39 @@ fn warning_event_adds_warning_history_cell() {
     );
 }
 
+#[test]
+fn stream_recovery_restores_previous_status_header() {
+    let (mut chat, mut rx, _op_rx) = make_chatwidget_manual();
+    chat.handle_codex_event(Event {
+        id: "task".into(),
+        msg: EventMsg::TaskStarted(TaskStartedEvent {
+            model_context_window: None,
+        }),
+    });
+    drain_insert_history(&mut rx);
+    chat.handle_codex_event(Event {
+        id: "retry".into(),
+        msg: EventMsg::StreamError(StreamErrorEvent {
+            message: "Reconnecting... 1/5".to_string(),
+            codex_error_info: Some(CodexErrorInfo::Other),
+        }),
+    });
+    drain_insert_history(&mut rx);
+    chat.handle_codex_event(Event {
+        id: "delta".into(),
+        msg: EventMsg::AgentMessageDelta(AgentMessageDeltaEvent {
+            delta: "hello".to_string(),
+        }),
+    });
+
+    let status = chat
+        .bottom_pane
+        .status_widget()
+        .expect("status indicator should be visible");
+    assert_eq!(status.header(), "Working");
+    assert!(chat.retry_status_header.is_none());
+}
+
 #[test]
 fn multiple_agent_messages_in_single_turn_emit_multiple_headers() {
     let (mut chat, mut rx, _op_rx) = make_chatwidget_manual();