feat(app): 移除内置agents并添加CORS支持和技能上传优化

移除了agents/registry.json中的所有内置agents配置，将agents数组清空。
为web应用添加了CORS中间件支持，允许指定的前端地址跨域访问。
重构了技能上传功能，增加了LLM重写机制，自动规范化上传的技能格式。
新增了工具名称提取逻辑，从技能正文中自动识别Required Tools段落。
更新了技能学习候选者和草稿的载荷结构，添加评估报告统计信息。
修改了意图路由技能的说明，改进任务状态管理逻辑。

app-instance/backend/tests/unit/test_main_agent_router.py

@@ -87,6 +87,14 @@ def _task() -> TaskRecord:
     )
 
 
+def _weather_task() -> TaskRecord:
+    task = _task()
+    task.description = "珠海天气怎样"
+    task.goal = "珠海天气怎样"
+    task.metadata["short_title"] = "查询珠海天气"
+    return task
+
+
 def test_router_continues_active_task_from_llm_decision() -> None:
     provider = RouterProvider('{"action":"continue_task","reason":"related","short_title":"任务连续性"}')
     decision = asyncio.run(
@@ -103,6 +111,35 @@ def test_router_continues_active_task_from_llm_decision() -> None:
     assert provider.calls[0]["max_tokens"] == 256
 
 
+def test_router_keeps_same_session_but_starts_new_task_for_standalone_weather_repeat() -> None:
+    decision = asyncio.run(
+        MainAgentRouter().classify(
+            "珠海天气怎么样",
+            active_task=_weather_task(),
+            provider=RouterProvider('{"action":"continue_task","reason":"neutral follow-up","short_title":"查询珠海天气"}'),
+        )
+    )
+
+    assert decision.is_task
+    assert decision.action == "create_task"
+    assert decision.starts_new_task is True
+    assert "fresh standalone task request" in decision.reason
+
+
+def test_router_allows_explicit_followup_to_continue_active_weather_task() -> None:
+    decision = asyncio.run(
+        MainAgentRouter().classify(
+            "顺便查一下深圳",
+            active_task=_weather_task(),
+            provider=RouterProvider('{"action":"continue_task","reason":"related follow-up","short_title":"查询珠海天气"}'),
+        )
+    )
+
+    assert decision.is_task
+    assert decision.action == "continue_task"
+    assert decision.starts_new_task is False
+
+
 def test_router_marks_revision_from_llm_decision() -> None:
     decision = asyncio.run(
         MainAgentRouter().classify(
@@ -163,6 +200,8 @@ def test_router_prompt_treats_unrelated_lightweight_conversation_as_new_topic()
     prompt = provider.calls[0]["messages"][1]["content"]
     assert "unrelated lightweight conversation" in prompt
     assert "must not be classified as revise_task merely because the active Task is awaiting acceptance" in prompt
+    assert "A Session is the durable conversation/device/group context" in prompt
+    assert "Repeating '珠海天气怎么样' later is a new Task" in prompt
 
 
 def test_router_closes_active_task_from_llm_decision() -> None: