feat: unified exec footer (#8067)

<img width="452" height="205" alt="Screenshot 2025-12-15 at 17 54 44"
src="https://github.com/user-attachments/assets/9ece0b1c-8387-4dfc-b883-c6a68ea1b663"
/>

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

@@ -426,6 +426,7 @@ fn make_chatwidget_manual(
         suppressed_exec_calls: HashSet::new(),
         last_unified_wait: None,
         task_complete_pending: false,
+        unified_exec_sessions: Vec::new(),
         mcp_startup_status: None,
         interrupts: InterruptManager::new(),
         reasoning_buffer: String::new(),
@@ -1219,7 +1220,7 @@ fn exec_end_without_begin_uses_event_command() {
 }
 
 #[test]
-fn exec_history_shows_unified_exec_startup_commands() {
+fn exec_history_skips_unified_exec_startup_commands() {
     let (mut chat, mut rx, _op_rx) = make_chatwidget_manual(None);
 
     let begin = begin_exec_with_source(
@@ -1236,11 +1237,31 @@ fn exec_history_shows_unified_exec_startup_commands() {
     end_exec(&mut chat, begin, "echo unified exec startup\n", "", 0);
 
     let cells = drain_insert_history(&mut rx);
-    assert_eq!(cells.len(), 1, "expected finalized exec cell to flush");
-    let blob = lines_to_single_string(&cells[0]);
     assert!(
-        blob.contains("• Ran echo unified exec startup"),
-        "expected startup command to render: {blob:?}"
+        cells.is_empty(),
+        "expected unified exec startup to render in footer only"
+    );
+}
+
+#[test]
+fn unified_exec_end_after_task_complete_is_suppressed() {
+    let (mut chat, mut rx, _op_rx) = make_chatwidget_manual(None);
+
+    let begin = begin_exec_with_source(
+        &mut chat,
+        "call-startup",
+        "echo unified exec startup",
+        ExecCommandSource::UnifiedExecStartup,
+    );
+    drain_insert_history(&mut rx);
+
+    chat.on_task_complete(None);
+    end_exec(&mut chat, begin, "", "", 0);
+
+    let cells = drain_insert_history(&mut rx);
+    assert!(
+        cells.is_empty(),
+        "expected unified exec end after task complete to be suppressed"
     );
 }