feat: 将项目从nano重命名为beaver并更新相关配置

- 将所有环境变量前缀从NANO_改为BEAVER_
- 更新README.md文档内容，包括项目介绍、组件说明和快速开始指南
- 修改.gitignore文件，添加auth-portal运行时路径排除规则
- 更新app-instance镜像标签从nano/app-instance改为beaver/app-instance
- 增强技能安全检查器，支持工具前缀白名单功能
- 添加技能草稿重新检查安全性API端点
- 扩展证据选择器，收集工具调用名称用于技能学习
- 改进技能合成器，基于实际调用的工具生成工具提示
- 优化路由超时处理机制，增加重试逻辑
- 更新后端架构文档，添加可视化入口和基础概念说明
- 实现在WebSocket消息中传递工具迭代次数信息

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

@@ -38,6 +38,39 @@ class RouterProvider(LLMProvider):
         return "stub-model"
 
 
+class SequenceRouterProvider(LLMProvider):
+    def __init__(self, responses: list[str | Exception]) -> None:
+        super().__init__()
+        self.responses = list(responses)
+        self.calls: list[dict] = []
+
+    async def chat(
+        self,
+        messages: list[dict],
+        tools: list[dict] | None = None,
+        model: str | None = None,
+        max_tokens: int = 4096,
+        temperature: float = 0.7,
+        thinking_enabled: bool | None = None,
+    ) -> LLMResponse:
+        self.calls.append(
+            {
+                "messages": messages,
+                "max_tokens": max_tokens,
+                "temperature": temperature,
+                "model": model,
+                "thinking_enabled": thinking_enabled,
+            }
+        )
+        response = self.responses.pop(0)
+        if isinstance(response, Exception):
+            raise response
+        return LLMResponse(content=response, finish_reason="stop", provider_name="stub", model="stub-model")
+
+    def get_default_model(self) -> str:
+        return "stub-model"
+
+
 def _task() -> TaskRecord:
     return TaskRecord(
         task_id="task-1",
@@ -133,3 +166,38 @@ def test_router_fallback_keeps_active_task_but_not_new_task() -> None:
 
     assert active.is_task
     assert not inactive.is_task
+
+
+def test_router_retries_once_after_provider_failure() -> None:
+    provider = SequenceRouterProvider(
+        [
+            TimeoutError(),
+            '{"action":"new_task","reason":"needs search","short_title":"中美会面"}',
+        ]
+    )
+
+    decision = asyncio.run(
+        MainAgentRouter().classify(
+            "帮我看看昨天的中美会面都谈了什么？",
+            provider=provider,
+        )
+    )
+
+    assert decision.is_task
+    assert decision.action == "create_task"
+    assert len(provider.calls) == 2
+
+
+def test_router_fallback_after_two_provider_failures() -> None:
+    provider = SequenceRouterProvider([TimeoutError(), RuntimeError("provider down")])
+
+    decision = asyncio.run(
+        MainAgentRouter().classify(
+            "帮我看看昨天的中美会面都谈了什么？",
+            provider=provider,
+        )
+    )
+
+    assert not decision.is_task
+    assert decision.reason == "router_failed: provider down"
+    assert len(provider.calls) == 2