fix(lint): 修复 PR #14 引入的 lint 回退 (119→0)

PR #14 从旧分支复制文件导致回退了 PR #10 的 lint 修复。
修复内容:
- autoflake 移除未使用导入/变量
- autopep8 修复缩进/空格
- 手动修复 F821(pathlib→Path), F541(f-string), F841(未使用变量)
- 所有修复均通过 flake8 --max-line-length=120 --extend-ignore=E501 检查 (0 errors)

src/daemon/guardrails.py

@@ -4,7 +4,7 @@ from __future__ import annotations
 
 import logging
 import re
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from pathlib import Path
 from typing import Any, Dict, List, Optional
 
@@ -38,7 +38,9 @@ class GuardrailEngine:
             data = yaml.safe_load(f)
         self.rules = data.get("rules", [])
         self.settings = data.get("settings", {"enabled": True})
-        logger.info("Loaded %d guardrail rules from %s", len(self.rules), config_path)
+        logger.info(
+            "Loaded %d guardrail rules from %s", len(
+                self.rules), config_path)
 
     def check_task(self, task: Any) -> List[GuardrailViolation]:
         """检查 Task 是否触犯安全红线（调度前调用）"""
@@ -95,7 +97,8 @@ class GuardrailEngine:
 
         return violations
 
-    def check_token_usage(self, token_count: int) -> Optional[GuardrailViolation]:
+    def check_token_usage(
+            self, token_count: int) -> Optional[GuardrailViolation]:
         """检查 Token 消耗是否超标"""
         if not self.settings.get("enabled", True):
             return None
@@ -103,7 +106,10 @@ class GuardrailEngine:
         for rule in self.rules:
             if rule["id"] != "high_token_usage":
                 continue
-            threshold = rule.get("triggers", [{}])[0].get("token_threshold", 100000)
+            threshold = rule.get(
+                "triggers", [
+                    {}])[0].get(
+                "token_threshold", 100000)
             if token_count > threshold:
                 return GuardrailViolation(
                     rule_id=rule["id"],
@@ -114,7 +120,8 @@ class GuardrailEngine:
                 )
         return None
 
-    def check_consecutive_failure(self, failure_count: int) -> Optional[GuardrailViolation]:
+    def check_consecutive_failure(
+            self, failure_count: int) -> Optional[GuardrailViolation]:
         """检查连续失败次数"""
         if not self.settings.get("enabled", True):
             return None
@@ -122,7 +129,10 @@ class GuardrailEngine:
         for rule in self.rules:
             if rule["id"] != "consecutive_failure":
                 continue
-            threshold = rule.get("triggers", [{}])[0].get("consecutive_failures", 3)
+            threshold = rule.get(
+                "triggers", [
+                    {}])[0].get(
+                "consecutive_failures", 3)
             if failure_count >= threshold:
                 return GuardrailViolation(
                     rule_id=rule["id"],