fix(cua-bench): add KeyAction support to worker client (#1088) (#1141)

The worker client only accepted HotkeyAction for key presses, but the
Slack oracle uses KeyAction(key="Return"). Add `key` to valid_fn_names
and handle it in check_and_fix_action so callers can express single-key
presses matching the oracle behavior.

Closes #1088

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: ddupont808

libs/cua-bench/cua_bench/workers/worker_client.py

@@ -14,6 +14,7 @@
     DoubleClickAction,
     DragAction,
     HotkeyAction,
+    KeyAction,
     RightClickAction,
     ScrollAction,
     TypeAction,
@@ -133,6 +134,7 @@ class CBEnvWorkerClient:
         "right_single",
         "drag",
         "hotkey",
+        "key",
         "type",
         "scroll",
         "wait",
@@ -271,6 +273,11 @@ def check_and_fix_action(self, action_str):
             args_str = ",".join(args)
             return f"hotkey({args_str})", HotkeyAction(keys=list(args))
 
+        elif fn_name == "key":
+            if not check_type(args, [str]):
+                return "wait()", default_action
+            return f"key({args[0]})", KeyAction(key=args[0])
+
         elif fn_name == "type":
             if not check_type(args, [str]):
                 return "wait()", default_action