feat(cli): show todo progress as done/total fraction

Parse the todo_tool result summary to display completion progress in
CLI tool preview lines:

  Read:    ┊ 📋 plan      3/4 task(s)  0.5s
  Update:  ┊ 📋 plan      update 3/4 ✓  0.5s
  Create:  falls back to plain count when no completed tasks

Falls back gracefully to the existing 'N task(s)' format when the
result is missing, malformed, or has no completed items.

Originally proposed in PR #17194 by Albert.Zhou; salvaged onto current
main.

Co-authored-by: Albert.Zhou <albert748@gmail.com>

agent/display.py

@@ -953,11 +953,29 @@ def get_cute_tool_message(
     if tool_name == "todo":
         todos_arg = args.get("todos")
         merge = args.get("merge", False)
+        # Parse result for completion progress
+        total = 0
+        done = 0
+        if result:
+            try:
+                data = safe_json_loads(result)
+                if data:
+                    s = data.get("summary", {})
+                    total = s.get("total", 0)
+                    done = s.get("completed", 0)
+            except Exception:
+                pass
         if todos_arg is None:
+            if total > 0:
+                return _wrap(f"┊ 📋 plan      {done}/{total} task(s)  {dur}")
             return _wrap(f"┊ 📋 plan      reading tasks  {dur}")
         elif merge:
+            if total > 0 and done > 0:
+                return _wrap(f"┊ 📋 plan      update {done}/{total} ✓  {dur}")
             return _wrap(f"┊ 📋 plan      update {len(todos_arg)} task(s)  {dur}")
         else:
+            if total > 0 and done > 0:
+                return _wrap(f"┊ 📋 plan      {done}/{total} task(s)  {dur}")
             return _wrap(f"┊ 📋 plan      {len(todos_arg)} task(s)  {dur}")
     if tool_name == "session_search":
         return _wrap(f"┊ 🔍 recall    \"{_trunc(args.get('query', ''), 35)}\"  {dur}")