phsl / new-api

• Introduced `useMinimumLoadingTime` to `MjLogsActions.jsx`, guaranteeing a minimum skeleton display duration for smoother UX
• Refactored loading state UI to use wrapped `Skeleton` with placeholder, matching the implementation in `UsageLogsActions.jsx`
• Kept existing banner, admin checks, and compact-mode toggle intact while streamlining the code
• Ensures consistent loading indicators across usage- and MJ-log tables