实现 AI Core 与 Agent Core 基础功能

- 更新 README 描述从后端壳子到 AI Core/Agent Core
- 添加 ToolCall 和 ToolResult 数据结构定义
- 扩展 AgentRun 模型增加输出、错误码、工具调用结果等字段
- 添加 mock 提供商类型支持
- 实现聊天、代理运行、工具调用和提供商管理的核心路由逻辑
- 集成容器化依赖注入和错误处理机制
- 更新 API 接口契约和文档说明

backend/app/agent/permissions.py

@@ -0,0 +1,80 @@
+import asyncio
+from dataclasses import dataclass
+from enum import Enum
+from uuid import uuid4
+
+
+class PermissionMode(str, Enum):
+    allow = "allow"
+    confirm = "confirm"
+    deny = "deny"
+
+
+class PermissionPolicy:
+    def __init__(self) -> None:
+        self._rules: dict[str, PermissionMode] = {
+            "notes.delete": PermissionMode.confirm,
+            "notes.write": PermissionMode.confirm,
+            "network.request": PermissionMode.confirm,
+            "secrets.use": PermissionMode.confirm,
+        }
+
+    def set_rule(self, permission: str, mode: PermissionMode) -> None:
+        self._rules[permission] = mode
+
+    def mode_for(self, permission: str | None) -> PermissionMode:
+        if permission is None:
+            return PermissionMode.allow
+        return self._rules.get(permission, PermissionMode.allow)
+
+
+@dataclass(slots=True)
+class PermissionTicket:
+    request_id: str
+    run_id: str
+    permission: str
+    future: asyncio.Future[str]
+
+
+class PermissionManager:
+    def __init__(self, policy: PermissionPolicy) -> None:
+        self.policy = policy
+        self._pending: dict[tuple[str, str], PermissionTicket] = {}
+        self._session_grants: set[str] = set()
+
+    def mode_for(self, permission: str | None) -> PermissionMode:
+        if permission in self._session_grants:
+            return PermissionMode.allow
+        return self.policy.mode_for(permission)
+
+    def create_ticket(self, run_id: str, permission: str) -> PermissionTicket:
+        ticket = PermissionTicket(
+            request_id=f"permission_{uuid4().hex}",
+            run_id=run_id,
+            permission=permission,
+            future=asyncio.get_running_loop().create_future(),
+        )
+        self._pending[(run_id, ticket.request_id)] = ticket
+        return ticket
+
+    async def wait(self, ticket: PermissionTicket, timeout: float) -> str:
+        try:
+            return await asyncio.wait_for(ticket.future, timeout=timeout)
+        finally:
+            self._pending.pop((ticket.run_id, ticket.request_id), None)
+
+    def resolve(self, run_id: str, request_id: str, decision: str) -> bool:
+        ticket = self._pending.get((run_id, request_id))
+        if ticket is None or ticket.future.done():
+            return False
+        if decision == "allow_session":
+            self._session_grants.add(ticket.permission)
+        ticket.future.set_result(decision)
+        return True
+
+    def cancel_run(self, run_id: str) -> None:
+        for key, ticket in list(self._pending.items()):
+            if ticket.run_id == run_id:
+                if not ticket.future.done():
+                    ticket.future.cancel()
+                self._pending.pop(key, None)