feat: add consent-based GA4 analytics

offline/OfflineApp.svelte

@@ -1,5 +1,6 @@
 <script lang="ts">
   import { onMount } from 'svelte';
+  import AnalyticsConsent from '../src/lib/components/AnalyticsConsent.svelte';
   import HomePage from '../src/routes/+page.svelte';
   import CardsPage from '../src/routes/cards/+page.svelte';
   import AnalysisPage from '../src/routes/analysis/+page.svelte';
@@ -108,6 +109,8 @@
 
 <svelte:component this={CurrentPage} />
 
+<AnalyticsConsent pagePath={currentPath} />
+
 <style>
   :global(*) { box-sizing: border-box; }
   :global(body) { margin: 0; background: #101319; color: #e8ebf1; font-family: Pretendard, "Noto Sans KR", sans-serif; }

offline/analytics.ts

@@ -0,0 +1,9 @@
+import type { AnalyticsClient } from '../src/lib/analytics/types.ts';
+
+export const analytics: AnalyticsClient = {
+  available: false,
+  readConsent: () => null,
+  grantConsent: () => {},
+  denyConsent: () => {},
+  trackPageView: () => {}
+};