Enhance workflow engine and frontend components with transition speech support

- Introduce edge transition speech functionality in the WorkflowEngine to provide optional speech during node transitions.
- Update pipeline execution to utilize the new transition speech feature, enhancing user experience by masking delays during transitions.
- Modify frontend components to support transition speech in edge specifications, allowing users to define and edit transition speech for edges.
- Refactor edge handling logic in the WorkflowEditor to accommodate the new transition speech field, improving workflow management capabilities.

backend/services/pipecat/pipeline.py

@@ -346,9 +346,18 @@ async def run_pipeline(transport, cfg: AssistantConfig) -> None:
         await emit_node_active(target)
         apply_node(target)
 
-    def make_transition_handler(target: str):
+    async def speak_transition(edge: dict | None) -> None:
+        """切换瞬间播报过渡语(可选),掩盖切节点/新一轮生成的延迟。不写入上下文。"""
+        speech = engine.edge_transition_speech(edge)
+        if speech:
+            await worker.queue_frame(TTSSpeakFrame(speech, append_to_context=False))
+
+    def make_transition_handler(edge: dict):
+        target = edge.get("target")
+
         async def handler(params):
             logger.info(f"LLM 触发转移 → {engine.name(target)}")
+            await speak_transition(edge)
             await go_to_node(target)
             # 返回工具结果,pipecat 随即在新节点的提示/工具下继续生成
             await params.result_callback({"status": "ok"})
@@ -372,6 +381,7 @@ async def run_pipeline(transport, cfg: AssistantConfig) -> None:
         )
         if target and target != wf_state["current"]:
             logger.info(f"文本兜底触发转移 → {engine.name(target)}")
+            await speak_transition(engine.find_edge(wf_state["current"], target))
             # 仅切换节点提示/工具,下一轮用户输入即在新节点处理
             await go_to_node(target)
 
@@ -379,10 +389,9 @@ async def run_pipeline(transport, cfg: AssistantConfig) -> None:
     # 由各节点的 context.tools 控制当前可见哪些)。
     if workflow_active:
         for edge in engine.edges:
-            target = edge.get("target")
-            if target:
+            if edge.get("target"):
                 llm.register_function(
-                    engine.edge_fn_name(edge), make_transition_handler(target)
+                    engine.edge_fn_name(edge), make_transition_handler(edge)
                 )
         apply_node(wf_state["current"])  # 设初始节点的提示与工具
 

backend/services/workflow_engine.py

@@ -50,6 +50,18 @@ class WorkflowEngine:
     def edge_condition(self, edge: dict) -> str:
         return (edge.get("data") or {}).get("condition") or ""
 
+    def edge_transition_speech(self, edge: dict | None) -> str:
+        """命中该边、切换节点瞬间播报的过渡语(可选,掩盖延迟,不写入上下文)。"""
+        if not edge:
+            return ""
+        return (edge.get("data") or {}).get("transition_speech") or ""
+
+    def find_edge(self, source: str | None, target: str | None) -> dict | None:
+        for edge in self.edges:
+            if edge.get("source") == source and edge.get("target") == target:
+                return edge
+        return None
+
     def edge_description(self, edge: dict) -> str:
         """作为转移函数的 description 交给 LLM:满足该条件时模型应调用此函数。"""
         cond = self.edge_condition(edge)