feat(sources): site center backend (credentials, refresh login, user data, health check, delete)

PUT /sites/{id}/credentials by kind (moved from auth-settings, legacy body
accepted), POST refresh-login (async task or wait), POST health-check,
GET user-data history, DELETE /sites/{id} (soft delete, releases kept),
DELETE /site-accounts/{id}, GET /sites?include=accounts; refreshSiteAccount
task with login-failure decisions and auto re-login on auth_expired;
scheduled jobs sites.user_data (6h) and sites.health_check (1h);
settings.sites defaults for rate limit, snapshot interval, UA and proxy.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

apps/web/app/components/workbench/release-fields.ts

@@ -76,6 +76,7 @@ export const ACCOUNT_STATUS: Record<SiteAccount["status"], { label: string; tone
   active: { label: "有效", tone: "success" },
   invalid: { label: "凭证无效", tone: "destructive" },
   expired: { label: "已过期", tone: "warning" },
+  challenge: { label: "需验证", tone: "warning" },
 };
 
 /** 站点下的账号总体状态:有效优先,其次最差的那个 */