fix: 避免无 cookie 时重复预热会话

app/scraping/services/site_session.py

@@ -266,7 +266,7 @@ class SiteSession:
         return reason.startswith("upstream status") or reason.startswith("httpx") or "Error:" in reason
 
     async def _ensure_warm(self, profile: _Profile) -> None:
-        """确保通道持有新鲜的 Akamai cookie；过期或缺失时访问首页预热"""
+        """确保通道有一次新鲜的首页预热；过期时重新访问首页"""
         if self._is_warm(profile):
             return
 
@@ -275,7 +275,10 @@ class SiteSession:
                 return
             try:
                 response = await profile.client.get(self._settings.home_url)
-                profile.warmed_at = time.monotonic()
+                # Akamai 不保证每次都下发 cookie；首页探测成功本身就是可复用的
+                # 预热结果，cookie 只用于观测和失败升级时的回灌。
+                if response.status_code < 400:
+                    profile.warmed_at = time.monotonic()
                 logger.info(
                     "会话预热完成：profile=%s status=%s cookies=%s",
                     profile.name,
@@ -285,14 +288,14 @@ class SiteSession:
             except httpx.HTTPError as exc:
                 # 预热失败不阻断本次抓取：直连目标页仍可能成功，只是慢
                 logger.warning("会话预热失败：profile=%s err=%s", profile.name, exc)
-                profile.warmed_at = time.monotonic()
+                profile.warmed_at = 0.0
 
     def _is_warm(self, profile: _Profile) -> bool:
         if not profile.warmed_at:
             return False
         if time.monotonic() - profile.warmed_at > self._settings.session_ttl_seconds:
             return False
-        return bool(profile.cookie_names & set(site.AKAMAI_COOKIE_NAMES))
+        return True
 
     async def _invalidate(self, profile: _Profile) -> None:
         """清空通道 cookie 并强制下次重新预热"""