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-header.tsx

@@ -1,30 +1,30 @@
 import Link from "next/link";
 
 export function SiteHeader() {
-  return (
-    <header className="sticky top-0 z-40 border-b bg-background/85 backdrop-blur motion-safe:animate-in motion-safe:fade-in motion-safe:slide-in-from-top-2 motion-safe:duration-500">
-      <div className="mx-auto flex w-full max-w-6xl items-center justify-between px-4 py-3 sm:px-8">
-        <Link
-          href="/"
-          className="text-sm font-semibold tracking-tight transition-colors duration-200 hover:text-primary sm:text-base"
-        >
-          Takasumi-Neodyマイクラサーバプロジェクト
-        </Link>
-        <nav className="flex items-center gap-4 text-sm">
-          <Link
-            href="/"
-            className="underline-offset-4 transition-colors duration-200 hover:text-primary hover:underline"
-          >
-            メインページ
-          </Link>
-          <Link
-            href="/announcements"
-            className="underline-offset-4 transition-colors duration-200 hover:text-primary hover:underline"
-          >
-            お知らせ
-          </Link>
-        </nav>
-      </div>
-    </header>
-  );
+	return (
+		<header className="sticky top-0 z-40 border-b bg-background/85 backdrop-blur motion-safe:animate-in motion-safe:fade-in motion-safe:slide-in-from-top-2 motion-safe:duration-500">
+			<div className="mx-auto flex w-full max-w-6xl items-center justify-between px-4 py-3 sm:px-8">
+				<Link
+					href="/"
+					className="text-sm font-semibold tracking-tight transition-colors duration-200 hover:text-primary sm:text-base"
+				>
+					Takasumi-Neodyマイクラサーバプロジェクト
+				</Link>
+				<nav className="flex items-center gap-4 text-sm">
+					<Link
+						href="/"
+						className="underline-offset-4 transition-colors duration-200 hover:text-primary hover:underline"
+					>
+						メインページ
+					</Link>
+					<Link
+						href="/announcements"
+						className="underline-offset-4 transition-colors duration-200 hover:text-primary hover:underline"
+					>
+						お知らせ
+					</Link>
+				</nav>
+			</div>
+		</header>
+	);
 }