phsl / new-api

Previously, the uptime status endpoint returned HTTP 400 with
“未配置 Uptime Kuma URL/Slug” when either option was not set, resulting in
frontend error states.

Changes:
• Treat absence of `UptimeKumaUrl` or `UptimeKumaSlug` as a valid scenario.
• Immediately respond with HTTP 200, `success: true`, and an empty `data` array.
• Preserve existing behavior when both options are provided.

This prevents unnecessary error notifications on the dashboard when
Uptime Kuma integration is not configured and improves overall UX.