feat: complete Week 1 frontend setup (#9 #10 #11 #12)

- Install and configure Tailwind CSS (#9)
- Install Nuxt UI component library (#10)
- Create app layout with header/footer components (#11)
- Implement Supabase client composable (#12)
- Add TypeScript database types
- Create placeholder pages (index, scan, settings)
- Setup responsive navigation with mobile menu
- Configure auth state management

All Week 1 frontend foundation tasks complete.

app/nuxt.config.ts

@@ -1,5 +1,21 @@
 // https://nuxt.com/docs/api/configuration/nuxt-config
 export default defineNuxtConfig({
   compatibilityDate: '2025-07-15',
-  devtools: { enabled: true }
+  devtools: { enabled: true },
+
+  modules: [
+    '@nuxt/ui',
+    '@nuxt/fonts'
+  ],
+
+  runtimeConfig: {
+    public: {
+      supabaseUrl: process.env.NUXT_PUBLIC_SUPABASE_URL || 'http://localhost:54321',
+      supabaseAnonKey: process.env.NUXT_PUBLIC_SUPABASE_ANON_KEY || ''
+    }
+  },
+
+  colorMode: {
+    preference: 'light'
+  }
 })