feat: 添加 Analytics 分析功能（行为追踪、错误码、协议更新）

docs/protocols/agent/sse-events.md

@@ -110,7 +110,7 @@ data: <json>
   "type": "STEP_STARTED",
   "threadId": "...",
   "runId": "...",
-  "stepName": "router" | "worker" | "memory"
+  "stepName": "router" | "worker"
 }
 ```
 
@@ -121,7 +121,7 @@ data: <json>
   "type": "STEP_FINISHED",
   "threadId": "...",
   "runId": "...",
-  "stepName": "router" | "worker" | "memory"
+  "stepName": "router" | "worker"
 }
 ```
 
@@ -137,7 +137,7 @@ data: <json>
   "messageId": "...",
   "toolCallId": "...",
   "toolCallName": "...",
-  "stage": "worker" | "memory"
+  "stage": "worker"
 }
 ```
 
@@ -152,7 +152,7 @@ data: <json>
   "toolCallId": "...",
   "toolCallName": "...",
   "args": {},
-  "stage": "worker" | "memory"
+  "stage": "worker"
 }
 ```
 
@@ -166,7 +166,7 @@ data: <json>
   "messageId": "...",
   "toolCallId": "...",
   "toolCallName": "...",
-  "stage": "worker" | "memory"
+  "stage": "worker"
 }
 ```
 
@@ -179,7 +179,7 @@ data: <json>
   "runId": "...",
   "messageId": "...",
   "role": "tool",
-  "stage": "worker" | "memory",
+  "stage": "worker",
   "tool_name": "...",
   "tool_call_id": "...",
   "tool_call_args": {},
@@ -239,7 +239,7 @@ SSE 协议中的工具名字段保持后端原样，不做服务端翻译：
   "runId": "...",
   "messageId": "...",
   "role": "assistant",
-  "stage": "worker" | "memory",
+  "stage": "worker",
   "status": "success" | "partial_success" | "failed",
   "answer": "...",
   "key_points": [],