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/api/toolchain_routes.py

@@ -46,7 +46,8 @@ _TTL_SECONDS = 7 * 24 * 3600
 _idempotency_lock = asyncio.Lock()
 
 
-def _is_duplicate(event: str, delivery: str, payload: Optional[Dict[str, Any]] = None) -> bool:
+def _is_duplicate(event: str, delivery: str,
+                  payload: Optional[Dict[str, Any]] = None) -> bool:
     """检查 Webhook 是否重复投递，自动清理过期条目。
 
     双重去重策略：
@@ -56,7 +57,8 @@ def _is_duplicate(event: str, delivery: str, payload: Optional[Dict[str, Any]] =
     """
     now = time.time()
     # 清理过期条目
-    while _delivery_timestamps and (now - _delivery_timestamps[0][0]) > _TTL_SECONDS:
+    while _delivery_timestamps and (
+            now - _delivery_timestamps[0][0]) > _TTL_SECONDS:
         _, key = _delivery_timestamps.pop(0)
         _delivery_cache.discard(key)
 
@@ -77,7 +79,11 @@ def _is_duplicate(event: str, delivery: str, payload: Optional[Dict[str, Any]] =
         content_hash = hashlib.sha256(content.encode()).hexdigest()[:16]
         content_key = f"content:{event}:{pr_num}:{sender}:{content_hash}"
         if content_key in _delivery_cache:
-            logger.info("Content-based duplicate detected: %s PR#%s by %s", event, pr_num, sender)
+            logger.info(
+                "Content-based duplicate detected: %s PR#%s by %s",
+                event,
+                pr_num,
+                sender)
             return True
         _delivery_cache.add(content_key)
         _delivery_timestamps.append((now, content_key))
@@ -137,8 +143,16 @@ async def _fetch_pr_files(repo: str, pr_number: int) -> Tuple[List[str], str]:
             last_error = str(e)
             if attempt < 2:
                 await asyncio.sleep(0.5 * (attempt + 1))
-                logger.warning("Retry %d/3 fetching PR files: %s/pulls/%d", attempt + 1, repo, pr_number)
-    logger.warning("Failed to fetch PR files after 3 retries: %s/pulls/%d - %s", repo, pr_number, last_error)
+                logger.warning(
+                    "Retry %d/3 fetching PR files: %s/pulls/%d",
+                    attempt + 1,
+                    repo,
+                    pr_number)
+    logger.warning(
+        "Failed to fetch PR files after 3 retries: %s/pulls/%d - %s",
+        repo,
+        pr_number,
+        last_error)
     return [], f"获取文件列表失败（重试3次）: {last_error}"
 
 
@@ -166,7 +180,6 @@ def _calc_risk_level(changed_files: List[str]) -> str:
 # ---------------------------------------------------------------------------
 
 
-
 MAIL_PROJECT_ID = "_mail"
 
 
@@ -252,7 +265,8 @@ async def _handle_pull_request(payload: Dict[str, Any]) -> None:
 
     pr = payload.get("pull_request")
     if not pr or not isinstance(pr, dict):
-        logger.warning("pull_request event missing pull_request field, skipping")
+        logger.warning(
+            "pull_request event missing pull_request field, skipping")
         return
     repo = _repo_fullname(payload)
     pr_number = pr.get("number", 0)
@@ -266,7 +280,8 @@ async def _handle_pull_request(payload: Dict[str, Any]) -> None:
     if fetch_error:
         file_list = f"⚠️ {fetch_error}"
     else:
-        file_list = "\n".join(f"- {f}" for f in changed_files) if changed_files else "(无文件变更)"
+        file_list = "\n".join(
+            f"- {f}" for f in changed_files) if changed_files else "(无文件变更)"
 
     text = render_template("review_request", {
         "repo": repo,
@@ -291,11 +306,13 @@ async def _handle_pull_request_review(payload: Dict[str, Any]) -> None:
     """
     review = payload.get("review")
     if not review or not isinstance(review, dict):
-        logger.warning("pull_request_review event missing review field, skipping")
+        logger.warning(
+            "pull_request_review event missing review field, skipping")
         return
     pr = payload.get("pull_request")
     if not pr or not isinstance(pr, dict):
-        logger.warning("pull_request_review event missing pull_request field, skipping")
+        logger.warning(
+            "pull_request_review event missing pull_request field, skipping")
         return
 
     # 兼容两种 payload 格式提取 state
@@ -319,7 +336,15 @@ async def _handle_pull_request_review(payload: Dict[str, Any]) -> None:
     pr_title = pr.get("title", "")
     pr_author = pr.get("user", {}).get("login", "unknown")
     # 兼容：org webhook 的 review 没有 user，从 sender 取
-    reviewer = review.get("user", {}).get("login", "") or payload.get("sender", {}).get("login", "unknown")
+    reviewer = review.get(
+        "user",
+        {}).get(
+        "login",
+        "") or payload.get(
+            "sender",
+            {}).get(
+                "login",
+        "unknown")
     review_body = review.get("body", "") or review.get("content", "(无评论)")
 
     result_map = {"APPROVED": "通过 ✓", "REQUEST_CHANGES": "驳回 ✗"}
@@ -366,7 +391,8 @@ async def _handle_issues(payload: Dict[str, Any]) -> None:
             logger.debug("Issue assigned but no assignee found, skipping")
             return
 
-        labels_list = [lbl.get("name", "") for lbl in (issue.get("labels") or [])]
+        labels_list = [lbl.get("name", "")
+                       for lbl in (issue.get("labels") or [])]
         labels = ", ".join(labels_list) if labels_list else "(无标签)"
         issue_body = issue.get("body", "(无描述)")
         brief = issue_title[:20].replace(" ", "-").lower()
@@ -417,7 +443,9 @@ async def _handle_issue_comment(payload: Dict[str, Any]) -> None:
 
     # 已关闭的 Issue/PR 不再发送 CI 失败通知
     if issue.get("state") == "closed":
-        logger.debug("Skipping CI failure notification for closed issue #%s", issue.get("number"))
+        logger.debug(
+            "Skipping CI failure notification for closed issue #%s",
+            issue.get("number"))
         return
 
     repo = _repo_fullname(payload)
@@ -485,7 +513,8 @@ async def gitea_webhook(
     # 1. 签名验证
     if not _verify_signature(body, x_gitea_signature):
         logger.warning("Webhook signature verification failed")
-        return Response(status_code=403, content="signature verification failed")
+        return Response(status_code=403,
+                        content="signature verification failed")
 
     # 3. 解析 payload（提前解析，用于幂等检查）
     try:
@@ -498,14 +527,18 @@ async def gitea_webhook(
     if x_gitea_event and x_gitea_delivery:
         async with _idempotency_lock:
             if _is_duplicate(x_gitea_event, x_gitea_delivery, payload):
-                logger.debug("Duplicate webhook: %s/%s", x_gitea_event, x_gitea_delivery)
+                logger.debug(
+                    "Duplicate webhook: %s/%s",
+                    x_gitea_event,
+                    x_gitea_delivery)
                 return Response(status_code=200, content="duplicate")
 
     # 4. 查找 handler
     handler = _EVENT_HANDLERS.get(x_gitea_event or "")
     if not handler:
         logger.debug("Unhandled event type: %s", x_gitea_event)
-        return Response(status_code=200, content=f"unhandled event: {x_gitea_event}")
+        return Response(status_code=200,
+                        content=f"unhandled event: {x_gitea_event}")
 
     # 5. 执行 handler
     try: