refactor: migrate authentication from Supabase to Better Auth and update project configuration

apps/frontend/.env.example

@@ -1,3 +1 @@
-VITE_SUPABASE_URL=https://your-project-ref.supabase.co
-VITE_SUPABASE_ANON_KEY=your-anon-key
 VITE_API_BASE_URL=http://localhost:3000

apps/frontend/package.json

@@ -18,7 +18,6 @@
     "@radix-ui/react-popover": "^1.1.2",
     "@radix-ui/react-slot": "^1.2.4",
     "@repo/api-contract": "workspace:*",
-    "@supabase/supabase-js": "^2.101.1",
     "@tanstack/react-query": "^5.96.1",
     "@tanstack/react-query-devtools": "^5.96.1",
     "@tanstack/react-router": "^1.168.10",
@@ -52,4 +51,4 @@
     "typescript": "~5.9.3",
     "vite": "^8.0.1"
   }
-}
+}

apps/frontend/vite.config.ts

@@ -22,9 +22,6 @@ export default defineConfig({
           if (id.includes('node_modules/@tanstack/react-router')) {
             return 'router-vendor';
           }
-          if (id.includes('node_modules/@supabase/supabase-js')) {
-            return 'supabase-vendor';
-          }
           if (id.includes('node_modules/radix-ui') || id.includes('node_modules/lucide-react')) {
             return 'ui-vendor';
           }