fix(context left after review): review footer context after /review (#5610)

## Summary
- show live review token usage while `/review` runs and restore the main
session indicator afterward
  - add regression coverage for the footer behavior

## Testing
  - just fmt
  - cargo test -p codex-tui

Fixes #5604

---------

Signed-off-by: Fahad <fahad@2doapp.com>

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

@@ -38,6 +38,9 @@ use codex_core::protocol::ReviewRequest;
 use codex_core::protocol::StreamErrorEvent;
 use codex_core::protocol::TaskCompleteEvent;
 use codex_core::protocol::TaskStartedEvent;
+use codex_core::protocol::TokenCountEvent;
+use codex_core::protocol::TokenUsage;
+use codex_core::protocol::TokenUsageInfo;
 use codex_core::protocol::UndoCompletedEvent;
 use codex_core::protocol::UndoStartedEvent;
 use codex_core::protocol::ViewImageToolCallEvent;
@@ -215,6 +218,81 @@ fn exited_review_mode_emits_results_and_finishes() {
     assert!(!chat.is_review_mode);
 }
 
+/// Exiting review restores the pre-review context window indicator.
+#[test]
+fn review_restores_context_window_indicator() {
+    let (mut chat, mut rx, _ops) = make_chatwidget_manual();
+
+    let context_window = 13_000;
+    let pre_review_tokens = 12_700; // ~30% remaining after subtracting baseline.
+    let review_tokens = 12_030; // ~97% remaining after subtracting baseline.
+
+    chat.handle_codex_event(Event {
+        id: "token-before".into(),
+        msg: EventMsg::TokenCount(TokenCountEvent {
+            info: Some(make_token_info(pre_review_tokens, context_window)),
+            rate_limits: None,
+        }),
+    });
+    assert_eq!(chat.bottom_pane.context_window_percent(), Some(30));
+
+    chat.handle_codex_event(Event {
+        id: "review-start".into(),
+        msg: EventMsg::EnteredReviewMode(ReviewRequest {
+            prompt: "Review the latest changes".to_string(),
+            user_facing_hint: "feature branch".to_string(),
+            append_to_original_thread: true,
+        }),
+    });
+
+    chat.handle_codex_event(Event {
+        id: "token-review".into(),
+        msg: EventMsg::TokenCount(TokenCountEvent {
+            info: Some(make_token_info(review_tokens, context_window)),
+            rate_limits: None,
+        }),
+    });
+    assert_eq!(chat.bottom_pane.context_window_percent(), Some(97));
+
+    chat.handle_codex_event(Event {
+        id: "review-end".into(),
+        msg: EventMsg::ExitedReviewMode(ExitedReviewModeEvent {
+            review_output: None,
+        }),
+    });
+    let _ = drain_insert_history(&mut rx);
+
+    assert_eq!(chat.bottom_pane.context_window_percent(), Some(30));
+    assert!(!chat.is_review_mode);
+}
+
+/// Receiving a TokenCount event without usage clears the context indicator.
+#[test]
+fn token_count_none_resets_context_indicator() {
+    let (mut chat, _rx, _ops) = make_chatwidget_manual();
+
+    let context_window = 13_000;
+    let pre_compact_tokens = 12_700;
+
+    chat.handle_codex_event(Event {
+        id: "token-before".into(),
+        msg: EventMsg::TokenCount(TokenCountEvent {
+            info: Some(make_token_info(pre_compact_tokens, context_window)),
+            rate_limits: None,
+        }),
+    });
+    assert_eq!(chat.bottom_pane.context_window_percent(), Some(30));
+
+    chat.handle_codex_event(Event {
+        id: "token-cleared".into(),
+        msg: EventMsg::TokenCount(TokenCountEvent {
+            info: None,
+            rate_limits: None,
+        }),
+    });
+    assert_eq!(chat.bottom_pane.context_window_percent(), None);
+}
+
 #[cfg_attr(
     target_os = "macos",
     ignore = "system configuration APIs are blocked under macOS seatbelt"
@@ -292,6 +370,7 @@ fn make_chatwidget_manual() -> (
         suppress_session_configured_redraw: false,
         pending_notification: None,
         is_review_mode: false,
+        pre_review_token_info: None,
         needs_final_message_separator: false,
         last_rendered_width: std::cell::Cell::new(None),
         feedback: codex_feedback::CodexFeedback::new(),
@@ -338,6 +417,21 @@ fn lines_to_single_string(lines: &[ratatui::text::Line<'static>]) -> String {
     s
 }
 
+fn make_token_info(total_tokens: i64, context_window: i64) -> TokenUsageInfo {
+    fn usage(total_tokens: i64) -> TokenUsage {
+        TokenUsage {
+            total_tokens,
+            ..TokenUsage::default()
+        }
+    }
+
+    TokenUsageInfo {
+        total_token_usage: usage(total_tokens),
+        last_token_usage: usage(total_tokens),
+        model_context_window: Some(context_window),
+    }
+}
+
 #[test]
 fn rate_limit_warnings_emit_thresholds() {
     let mut state = RateLimitWarningState::default();