chore: finish frontend ESLint migration #18

Enable every plugin recommended preset and replace Biome with ESLint formatting.

Preserve API contracts and JSX whitespace; verify source, tests, builds and tooling.

packages/ui/src/LoadingSkeleton/LoadingSkeleton.tsx

@@ -1,6 +1,7 @@
-import { Stack } from "@mantine/core";
 import type { FC, PropsWithChildren } from "react";
 
+import { Stack } from "@mantine/core";
+
 type LoadingSkeletonProps = PropsWithChildren<{
 	label: string;
 }>;