feat(auth): separate read and write bilibili accounts

reaction_board/services/snapshot.py

@@ -255,7 +255,7 @@ class SnapshotService:
     # ------------------------------------------------------------ internals
 
     def _check_auth(self, cfg: AppConfig, now: int) -> tuple[bool, str]:
-        if not cfg.bilibili.cookie:
+        if not cfg.bilibili.read.cookie:
             self.repo.kv_set("auth:last_check", str(now))
             self.repo.kv_set("auth:ok", "0")
             self.repo.kv_set("auth:message", "未配置 cookie")