refactor: standardize code formatting across components and utilities

- Updated formatting in SiteFooter and SiteHeader components for consistency.
- Refactored Badge, Button, Card, Separator components to improve readability.
- Enhanced markdown parsing logic in announcements and markdown utility functions.
- Adjusted ESLint configuration for better code quality checks.
- Added biome.json for BiomeJS configuration.
- Updated package.json and configuration files for improved dependency management.

components/site-footer.tsx

@@ -1,17 +1,17 @@
 export function SiteFooter() {
-  return (
-    <footer className="border-t bg-card/60">
-      <div className="mx-auto flex w-full max-w-6xl items-center justify-center px-4 py-4 text-center text-xs text-muted-foreground sm:px-8 sm:text-sm">
-        運用元:
-        <a
-          href="https://neody.land/ja"
-          target="_blank"
-          rel="noopener noreferrer"
-          className="ml-1 font-medium text-foreground underline underline-offset-4 hover:text-primary"
-        >
-          Neodyland
-        </a>
-      </div>
-    </footer>
-  );
-}
+	return (
+		<footer className="border-t bg-card/60">
+			<div className="mx-auto flex w-full max-w-6xl items-center justify-center px-4 py-4 text-center text-xs text-muted-foreground sm:px-8 sm:text-sm">
+				運用元:
+				<a
+					href="https://neody.land/ja"
+					target="_blank"
+					rel="noopener noreferrer"
+					className="ml-1 font-medium text-foreground underline underline-offset-4 hover:text-primary"
+				>
+					Neodyland
+				</a>
+			</div>
+		</footer>
+	);
+}