chore: bootstrap development environment

src/routes/+page.svelte

@@ -0,0 +1,47 @@
+<svelte:head>
+  <title>Holodream Tools</title>
+  <meta name="description" content="홀로드림스 통합 덱 최적화 도구" />
+</svelte:head>
+
+<main>
+  <section class="panel">
+    <p class="eyebrow">Development Environment</p>
+    <h1>Holodream Tools</h1>
+    <p>통합 덱 최적화 사이트의 기본 개발 환경이 준비되었습니다.</p>
+
+    <div class="status">
+      <span class="dot"></span>
+      <span>SvelteKit 서버가 실행 중입니다.</span>
+    </div>
+  </section>
+</main>
+
+<style>
+  :global(*) { box-sizing: border-box; }
+  :global(body) {
+    margin: 0;
+    min-width: 320px;
+    min-height: 100vh;
+    font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
+    color: #e5e7eb;
+    background: #0b1020;
+  }
+  main {
+    min-height: 100vh;
+    display: grid;
+    place-items: center;
+    padding: 24px;
+  }
+  .panel {
+    width: min(680px, 100%);
+    padding: 36px;
+    border: 1px solid #27324a;
+    border-radius: 18px;
+    background: #111827;
+  }
+  .eyebrow { color: #93c5fd; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; font-size: 12px; }
+  h1 { margin: 8px 0 12px; font-size: clamp(32px, 6vw, 52px); }
+  p { color: #aeb8c8; line-height: 1.65; }
+  .status { margin-top: 28px; display: flex; align-items: center; gap: 10px; color: #d1fae5; }
+  .dot { width: 10px; height: 10px; border-radius: 999px; background: #34d399; box-shadow: 0 0 16px #34d399; }
+</style>

src/routes/api/health/+server.ts

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+import { json } from '@sveltejs/kit';
+import { checkDatabase } from '$lib/server/db/client';
+
+export function GET() {
+  const checkedAt = new Date().toISOString();
+
+  try {
+    checkDatabase();
+
+    return json({
+      ok: true,
+      service: 'holodream-tools',
+      database: 'ok',
+      checkedAt
+    });
+  } catch (error) {
+    console.error('Health check failed', error);
+
+    return json(
+      {
+        ok: false,
+        service: 'holodream-tools',
+        database: 'unavailable',
+        checkedAt
+      },
+      { status: 503 }
+    );
+  }
+}