feat: implement PWA scaffold, dark design system, and 3-tab glassmorphism nav

- Add @serwist/next for PWA service worker (precaching, offline support)
- Create public/manifest.json with dark theme (#0a0a0f) and SVG icons
- Rewrite globals.css with full dark premium design system (Tailwind v4)
  - Design tokens: bg-deep, bg-card, gold, nur-purple, emerald, borders, text
  - Utility classes: .glass, .glass-light, .gold-gradient, .nur-gradient, .gold-purple-gradient
  - Prayer ring SVG styles
- Replace old 5-tab nav with 3-tab floating glassmorphism pill
  - Home (House), Nur center raised 56px gold-purple circle, Profile (User)
  - Active gold #D4AF37, inactive #666, safe-area-aware
- Create src/lib/api/wordpress.ts fetchAPI wrapper with JWT auth
- Update layout.tsx with manifest, apple-web-app, Viewport export

next.config.ts

@@ -1,7 +1,13 @@
-import type { NextConfig } from "next";
+import type { NextConfig } from 'next'
+import withSerwistInit from '@serwist/next'
+
+const withSerwist = withSerwistInit({
+  swSrc: 'src/sw.ts',
+  swDest: 'public/sw.js',
+})
 
 const nextConfig: NextConfig = {
-  output: process.env.NETLIFY === "true" ? undefined : "standalone",
-};
+  output: process.env.NETLIFY === 'true' ? undefined : 'standalone',
+}
 
-export default nextConfig;
+export default withSerwist(nextConfig)