fix(wecom-callback): retry send with fresh token on errcode 40001/42001

When WeCom returns errcode=40001 (invalid credential) or 42001 (token
expired), send() was returning a failure without evicting the bad token
from _access_tokens. All subsequent sends then kept using the same
invalid cached token until its TTL naturally expired (~7200s).

Fix: on the first token-rejection errcode, evict the cache entry and
retry once with a freshly fetched token. Non-token errcodes fail
immediately as before. If the refreshed token also fails, the error
is returned without looping further.

Adds four regression tests covering: successful retry on 40001,
successful retry on 42001, no retry on unrelated errcode, and clean
failure when the refresh does not help.

gateway/platforms/wecom_callback.py

@@ -187,7 +187,6 @@ class WecomCallbackAdapter(BasePlatformAdapter):
         app = self._resolve_app_for_chat(chat_id)
         touser = chat_id.split(":", 1)[1] if ":" in chat_id else chat_id
         try:
-            token = await self._get_access_token(app)
             payload = {
                 "touser": touser,
                 "msgtype": "text",
@@ -195,18 +194,31 @@ class WecomCallbackAdapter(BasePlatformAdapter):
                 "text": {"content": content[:2048]},
                 "safe": 0,
             }
-            resp = await self._http_client.post(
-                f"https://qyapi.weixin.qq.com/cgi-bin/message/send?access_token={token}",
-                json=payload,
-            )
-            data = resp.json()
-            if data.get("errcode") != 0:
-                return SendResult(success=False, error=str(data))
-            return SendResult(
-                success=True,
-                message_id=str(data.get("msgid", "")),
-                raw_response=data,
-            )
+            for _attempt in range(2):
+                token = await self._get_access_token(app)
+                resp = await self._http_client.post(
+                    f"https://qyapi.weixin.qq.com/cgi-bin/message/send?access_token={token}",
+                    json=payload,
+                )
+                data = resp.json()
+                errcode = data.get("errcode")
+                if errcode in {40001, 42001} and _attempt == 0:
+                    # WeCom rejected the token — evict the cached entry so
+                    # the next _get_access_token call forces a fresh fetch.
+                    logger.warning(
+                        "[WecomCallback] Token rejected for app '%s' (errcode=%s), refreshing",
+                        app.get("name", "default"), errcode,
+                    )
+                    self._access_tokens.pop(app["name"], None)
+                    continue
+                if errcode != 0:
+                    return SendResult(success=False, error=str(data))
+                return SendResult(
+                    success=True,
+                    message_id=str(data.get("msgid", "")),
+                    raw_response=data,
+                )
+            return SendResult(success=False, error="send failed after token refresh")
         except Exception as exc:
             return SendResult(success=False, error=str(exc))