feat(tui): add PR summary statusline items (#20892)

## Why?

The Codex App already exposes branch and PR context in its
branch-details UI. This brings the same context into the CLI footer as
opt-in statusline items, so users can choose the extra signal without
making the default footer busier.

## What?

Add optional `pull-request-number` and `branch-changes` items to the
configurable TUI status line.

- `pull-request-number` shows the open PR for the current checkout and
renders as a clickable terminal hyperlink when OSC 8 links are
supported.
- `branch-changes` shows committed additions/deletions against the
repository default branch, or `No changes` when the branch has no
committed diff.

<img width="1257" height="261" alt="CleanShot 2026-05-03 at 20 44 15"
src="https://github.com/user-attachments/assets/10b4380b-c3e9-4729-9ee1-3f742068fa47"
/>

## Architecture

This follows the same client/app-server split as the Codex App: the TUI
owns presentation, caching, and optional rendering, while
workspace-sensitive `git` and `gh` discovery runs through app-server.

The new TUI-local `workspace_command` layer sends bounded,
non-interactive `command/exec` requests to the active app-server. That
makes the implementation remote-friendly: the TUI does not decide
whether commands run in an embedded local workspace or a remote
workspace, and it does not bypass app-server sandbox or permission
policy.

The branch summary logic stays internal to `codex-tui` because this PR
only needs TUI statusline behavior. The command boundary is still
isolated behind `WorkspaceCommandExecutor`, so the lookup code can be
lifted or reused later without changing statusline rendering.

## How?

- Add a TUI `WorkspaceCommandExecutor` abstraction backed by app-server
`command/exec`.
- Add branch summary probes for:
  - current branch name,
  - open PR metadata,
  - committed branch diff stats against the default branch.
- Prefer remote-tracking default branch refs for diff stats, avoiding
stale or absent local `main` branches.
- Resolve PRs with `gh pr view` first, then fall back to
commit-associated PR lookup across parent/fork repos.
- Add `/statusline` picker entries, preview values, rendering, and OSC 8
clickable PR links.
- Keep all probes best-effort so missing `git`, missing `gh`, auth
failures, or non-git directories hide optional items instead of
surfacing footer errors.

## Validation

- `cargo test -p codex-tui branch_summary -- --nocapture`
- Snapshot coverage for the `/statusline` preview/setup rendering paths
- Hyperlink rendering coverage for clickable PR statusline cells

codex-rs/tui/src/bottom_pane/chat_composer.rs

@@ -190,6 +190,7 @@ use crate::keymap::EditorKeymap;
 use crate::keymap::RuntimeKeymap;
 use crate::keymap::VimNormalKeymap;
 use crate::keymap::primary_binding;
+use crate::onboarding::mark_underlined_hyperlink;
 use crate::render::Insets;
 use crate::render::RectExt;
 use crate::render::renderable::Renderable;
@@ -396,6 +397,7 @@ pub(crate) struct ChatComposer {
     side_conversation_active: bool,
     is_zellij: bool,
     status_line_value: Option<Line<'static>>,
+    status_line_hyperlink_url: Option<String>,
     status_line_enabled: bool,
     side_conversation_context_label: Option<String>,
     // Agent label injected into the footer's contextual row when multi-agent mode is active.
@@ -580,6 +582,7 @@ impl ChatComposer {
                 Some(codex_terminal_detection::Multiplexer::Zellij {})
             ),
             status_line_value: None,
+            status_line_hyperlink_url: None,
             status_line_enabled: false,
             side_conversation_context_label: None,
             active_agent_label: None,
@@ -4037,6 +4040,14 @@ impl ChatComposer {
         true
     }
 
+    pub(crate) fn set_status_line_hyperlink(&mut self, url: Option<String>) -> bool {
+        if self.status_line_hyperlink_url == url {
+            return false;
+        }
+        self.status_line_hyperlink_url = url;
+        true
+    }
+
     pub(crate) fn set_status_line_enabled(&mut self, enabled: bool) -> bool {
         if self.status_line_enabled == enabled {
             return false;
@@ -4441,6 +4452,11 @@ impl ChatComposer {
                     if show_right && let Some(line) = &right_line {
                         render_context_right(hint_rect, buf, line);
                     }
+                    if status_line_active
+                        && let Some(url) = self.status_line_hyperlink_url.as_deref()
+                    {
+                        mark_underlined_hyperlink(buf, hint_rect, url);
+                    }
                 }
             }
         }
@@ -5022,6 +5038,39 @@ mod tests {
         );
     }
 
+    #[test]
+    fn status_line_hyperlink_marks_pr_number_cells() {
+        let (tx, _rx) = unbounded_channel::<AppEvent>();
+        let sender = AppEventSender::new(tx);
+        let mut composer = ChatComposer::new(
+            /*has_input_focus*/ true,
+            sender,
+            /*enhanced_keys_supported*/ true,
+            "Ask Codex to do anything".to_string(),
+            /*disable_paste_burst*/ false,
+        );
+        let url = "https://github.com/openai/codex/pull/20252";
+        composer.set_status_line_enabled(/*enabled*/ true);
+        composer.set_status_line(Some(Line::from(Span::styled(
+            "PR #20252",
+            Style::default().cyan().underlined(),
+        ))));
+        composer.set_status_line_hyperlink(Some(url.to_string()));
+
+        let area = Rect::new(0, 0, 40, 6);
+        let mut buf = Buffer::empty(area);
+        composer.render(area, &mut buf);
+
+        let marked_cells = (area.top()..area.bottom())
+            .flat_map(|y| (area.left()..area.right()).map(move |x| (x, y)))
+            .filter(|&(x, y)| buf[(x, y)].symbol().contains(url))
+            .count();
+        assert_eq!(
+            marked_cells,
+            "PR #20252".chars().filter(|ch| !ch.is_whitespace()).count()
+        );
+    }
+
     #[test]
     fn esc_exits_empty_shell_mode() {
         use crossterm::event::KeyCode;

codex-rs/tui/src/bottom_pane/mod.rs

@@ -1544,6 +1544,12 @@ impl BottomPane {
         }
     }
 
+    pub(crate) fn set_status_line_hyperlink(&mut self, url: Option<String>) {
+        if self.composer.set_status_line_hyperlink(url) {
+            self.request_redraw();
+        }
+    }
+
     pub(crate) fn set_status_line_enabled(&mut self, enabled: bool) {
         if self.composer.set_status_line_enabled(enabled) {
             self.request_redraw();

codex-rs/tui/src/bottom_pane/snapshots/codex_tui__bottom_pane__status_line_setup__tests__setup_view_snapshot_uses_runtime_preview_values.snap

@@ -15,7 +15,7 @@ expression: "render_lines(&view, 72)"
   [x] git-branch            Current Git branch (omitted when unavaila…  
   [ ] model-with-reasoning  Current model name with reasoning level     
   [ ] project-name          Project name (omitted when unavailable)     
-  [ ] run-state             Compact session run-state text (Ready, Wo…  
+  [ ] pull-request-number   Open pull request number for the current …  
                                                                         
   gpt-5-codex · ~/codex-rs · jif/statusline-preview                     
   Use ↑↓ to navigate, ←→ to move, space to select, enter to confirm, esc

codex-rs/tui/src/bottom_pane/status_line_setup.rs

@@ -71,6 +71,12 @@ pub(crate) enum StatusLineItem {
     /// Current git branch name (if in a repository).
     GitBranch,
 
+    /// Open pull request number for the current branch.
+    PullRequestNumber,
+
+    /// Committed branch diff stats relative to the default branch.
+    BranchChanges,
+
     /// Compact runtime run-state text.
     #[strum(to_string = "run-state", serialize = "status")]
     Status,
@@ -127,6 +133,12 @@ impl StatusLineItem {
             StatusLineItem::CurrentDir => "Current working directory",
             StatusLineItem::ProjectRoot => "Project name (omitted when unavailable)",
             StatusLineItem::GitBranch => "Current Git branch (omitted when unavailable)",
+            StatusLineItem::PullRequestNumber => {
+                "Open pull request number for the current branch (omitted when unavailable)"
+            }
+            StatusLineItem::BranchChanges => {
+                "Committed branch changes against the default branch (omitted when unavailable)"
+            }
             StatusLineItem::Status => "Compact session run-state text (Ready, Working, Thinking)",
             StatusLineItem::ContextRemaining => {
                 "Percentage of context window remaining (omitted when unknown)"
@@ -165,6 +177,8 @@ impl StatusLineItem {
             StatusLineItem::CurrentDir => StatusSurfacePreviewItem::CurrentDir,
             StatusLineItem::ProjectRoot => StatusSurfacePreviewItem::ProjectRoot,
             StatusLineItem::GitBranch => StatusSurfacePreviewItem::GitBranch,
+            StatusLineItem::PullRequestNumber => StatusSurfacePreviewItem::PullRequestNumber,
+            StatusLineItem::BranchChanges => StatusSurfacePreviewItem::BranchChanges,
             StatusLineItem::Status => StatusSurfacePreviewItem::Status,
             StatusLineItem::ContextRemaining => StatusSurfacePreviewItem::ContextRemaining,
             StatusLineItem::ContextUsed => StatusSurfacePreviewItem::ContextUsed,
@@ -409,6 +423,18 @@ mod tests {
         );
     }
 
+    #[test]
+    fn git_summary_items_are_selectable_ids() {
+        assert_eq!(
+            "pull-request-number".parse::<StatusLineItem>(),
+            Ok(StatusLineItem::PullRequestNumber)
+        );
+        assert_eq!(
+            "branch-changes".parse::<StatusLineItem>(),
+            Ok(StatusLineItem::BranchChanges)
+        );
+    }
+
     #[test]
     fn parse_status_line_items_accepts_title_only_variants() {
         let items = ["run-state", "task-progress"]

codex-rs/tui/src/bottom_pane/status_line_style.rs

@@ -32,7 +32,9 @@ impl StatusLineAccent {
         match item {
             StatusLineItem::ModelName | StatusLineItem::ModelWithReasoning => Self::Model,
             StatusLineItem::CurrentDir | StatusLineItem::ProjectRoot => Self::Path,
-            StatusLineItem::GitBranch => Self::Branch,
+            StatusLineItem::GitBranch
+            | StatusLineItem::PullRequestNumber
+            | StatusLineItem::BranchChanges => Self::Branch,
             StatusLineItem::Status => Self::State,
             StatusLineItem::ContextRemaining
             | StatusLineItem::ContextUsed
@@ -106,6 +108,11 @@ where
         } else {
             Style::default().dim()
         };
+        let style = if item == StatusLineItem::PullRequestNumber {
+            style.underlined()
+        } else {
+            style
+        };
         spans.push(Span::styled(text, style));
     }
 
@@ -256,6 +263,25 @@ mod tests {
         assert!(line.spans[2].style.add_modifier.contains(Modifier::DIM));
     }
 
+    #[test]
+    fn pull_request_number_uses_link_style() {
+        let line = status_line_from_segments_with_resolver(
+            [(StatusLineItem::PullRequestNumber, "PR #20252".to_string())],
+            /*use_theme_colors*/ false,
+            |_| None,
+        )
+        .expect("status line");
+
+        assert_eq!(line.spans[0].style.fg, None);
+        assert!(line.spans[0].style.add_modifier.contains(Modifier::DIM));
+        assert!(
+            line.spans[0]
+                .style
+                .add_modifier
+                .contains(Modifier::UNDERLINED)
+        );
+    }
+
     #[test]
     fn status_line_segments_return_none_when_empty() {
         assert_eq!(

codex-rs/tui/src/bottom_pane/status_surface_preview.rs

@@ -14,6 +14,8 @@ pub(crate) enum StatusSurfacePreviewItem {
     Status,
     ThreadTitle,
     GitBranch,
+    PullRequestNumber,
+    BranchChanges,
     ContextRemaining,
     ContextUsed,
     FiveHourLimit,
@@ -40,6 +42,8 @@ impl StatusSurfacePreviewItem {
             StatusSurfacePreviewItem::Status => "Working",
             StatusSurfacePreviewItem::ThreadTitle => "thread title",
             StatusSurfacePreviewItem::GitBranch => "feat/awesome-feature",
+            StatusSurfacePreviewItem::PullRequestNumber => "PR #123",
+            StatusSurfacePreviewItem::BranchChanges => "+12 -3",
             StatusSurfacePreviewItem::ContextRemaining => "Context 0% left",
             StatusSurfacePreviewItem::ContextUsed => "Context 0% used",
             StatusSurfacePreviewItem::FiveHourLimit => "5h 0%",
@@ -66,6 +70,8 @@ impl StatusSurfacePreviewItem {
             Self::Status,
             Self::ThreadTitle,
             Self::GitBranch,
+            Self::PullRequestNumber,
+            Self::BranchChanges,
             Self::ContextRemaining,
             Self::ContextUsed,
             Self::FiveHourLimit,