feat(vla): align transformer training stack and rollout validation

tests/test_eval_vla_execution.py

@@ -0,0 +1,28 @@
+import unittest
+
+from roboimi.vla.eval_utils import execute_policy_action
+
+
+class _FakeEnv:
+    def __init__(self):
+        self.calls = []
+
+    def step(self, action):
+        self.calls.append(("step", action))
+
+    def step_jnt(self, action):
+        self.calls.append(("step_jnt", action))
+
+
+class EvalVLAExecutionTest(unittest.TestCase):
+    def test_execute_policy_action_uses_ee_step(self):
+        env = _FakeEnv()
+        action = [1, 2, 3]
+
+        execute_policy_action(env, action)
+
+        self.assertEqual(env.calls, [("step", action)])
+
+
+if __name__ == "__main__":
+    unittest.main()