feat: make workflow messages resumable

backend/tests/test_workflow_v3.py

@@ -111,22 +111,27 @@ class WorkflowGraphTests(unittest.TestCase):
         self.assertTrue(body.vision_enabled)
         self.assertIsNone(body.vision_model_resource_id)
 
-    def test_agent_entry_mode_defaults_and_validation(self):
+    def test_agent_entry_modes_only_control_conversation_start(self):
         graph = valid_graph()
         normalized = normalize_graph(graph)
         agent = next(node for node in normalized["nodes"] if node["type"] == "agent")
         self.assertEqual(agent["data"]["entryMode"], "wait_user")
-        self.assertEqual(agent["data"]["entrySpeech"], "")
+        self.assertNotIn("entrySpeech", agent["data"])
         self.assertTrue(agent["data"]["inheritGlobalConfig"])
         self.assertEqual(agent["data"]["contextPolicy"], "fresh")
 
-        agent["data"]["entryMode"] = "fixed_speech"
-        self.assertTrue(
-            any("固定进入语不能为空" in error for error in validate_graph(normalized))
-        )
-        agent["data"]["entrySpeech"] = "您好，{{customer}}"
+        agent["data"]["entryMode"] = "generate"
         self.assertEqual(validate_graph(normalized), [])
 
+        agent["data"]["entryMode"] = "fixed_speech"
+        agent["data"]["entrySpeech"] = "您好，{{customer}}"
+        cleaned = normalize_graph(normalized)
+        cleaned_agent = next(
+            node for node in cleaned["nodes"] if node["type"] == "agent"
+        )
+        self.assertEqual(cleaned_agent["data"]["entryMode"], "wait_user")
+        self.assertNotIn("entrySpeech", cleaned_agent["data"])
+
     def test_action_defaults_preserve_legacy_result_assignment_behavior(self):
         graph = valid_graph()
         graph["nodes"].extend(