chore: ruff 代码检查与修复

130 issues auto-fixed (import ordering, UP045/UP006 type annotations),
33 issues manually fixed (E712/E501/E402/E722 + N818 rename + per-file
wechat ignore for N8xx naming conventions). All 33 tests pass.

app/wechat/handler.py

@@ -1,8 +1,7 @@
-import xml.etree.cElementTree as ET
-from typing import Optional
+import xml.etree.ElementTree as ET
 
-from app.wechat.crypto import WXBizMsgCrypt
 from app.config import settings
+from app.wechat.crypto import WXBizMsgCrypt
 
 
 class WeChatMessageHandler:
@@ -15,7 +14,7 @@ class WeChatMessageHandler:
 
     def verify_url(
         self, msg_signature: str, timestamp: str, nonce: str, echostr: str
-    ) -> Optional[str]:
+    ) -> str | None:
         ret, sEchoStr = self.wxcpt.VerifyURL(
             msg_signature, timestamp, nonce, echostr
         )
@@ -33,7 +32,7 @@ class WeChatMessageHandler:
         msg_signature: str,
         timestamp: str,
         nonce: str,
-    ) -> Optional[ET.Element]:
+    ) -> ET.Element | None:
         ret, xml_content = self.wxcpt.DecryptMsg(
             post_data, msg_signature, timestamp, nonce
         )
@@ -43,16 +42,16 @@ class WeChatMessageHandler:
 
     def encrypt_response(
         self, response_xml: str, nonce: str, timestamp: str
-    ) -> Optional[str]:
+    ) -> str | None:
         ret, encrypted = self.wxcpt.EncryptMsg(response_xml, nonce, timestamp)
         if ret == 0:
             return encrypted
         return None
 
     def handle_event(
-        self, event: str, event_key: Optional[str], from_user: str
-    ) -> Optional[str]:
+        self, event: str, event_key: str | None, from_user: str
+    ) -> str | None:
         return None
 
-    def handle_text(self, content: str, from_user: str) -> Optional[str]:
+    def handle_text(self, content: str, from_user: str) -> str | None:
         return None