chore: lint 修复（TC001/TC003 类型导入优化）

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

core/agent/protocols.py

@@ -1,11 +1,13 @@
 """Agent 专属 Protocol 端口。"""
+
 from __future__ import annotations
 
-from typing import Any, Protocol, runtime_checkable
+from typing import TYPE_CHECKING, Any, Protocol, runtime_checkable
 
 import pluggy
 
-from core.agent.types import LoopResult, Step
+if TYPE_CHECKING:
+    from core.agent.types import LoopResult, Step
 
 hookspec = pluggy.HookspecMarker("agent_loop")
 hookimpl = pluggy.HookimplMarker("agent_loop")
@@ -27,19 +29,13 @@ class AgentLoopSpec:
     """
 
     @hookspec
-    async def before_step(
-        self, iteration: int, messages: list[dict[str, Any]]
-    ) -> None: ...
+    async def before_step(self, iteration: int, messages: list[dict[str, Any]]) -> None: ...
 
     @hookspec
-    async def after_tool(
-        self, iteration: int, step: Step
-    ) -> str | None: ...
+    async def after_tool(self, iteration: int, step: Step) -> str | None: ...
 
     @hookspec
-    async def after_step(
-        self, iteration: int, messages: list[dict[str, Any]]
-    ) -> None: ...
+    async def after_step(self, iteration: int, messages: list[dict[str, Any]]) -> None: ...
 
     @hookspec
     async def on_finish(self, result: LoopResult) -> None: ...