Refactor: Auth Routes & Global Layout Structure

[Sunja-An]

Refactor: Auth Routes & Global Layout Structure

♻️ Architecture Changes

• Route Grouping: Moved authentication-related pages (Login, Signup) into a dedicated (auth) route group to separate them from the main application layout ((main)).
  • src/app/(main)/login -> src/app/(auth)/login
  • src/app/(auth)/signup (New)
• Global Providers: Centralized context providers (QueryClient, Theme, Auth) into src/app/providers.tsx to keep the Root Layout clean.

🎨 Layout & UI

• Global Error Handling: Added error.tsx and not-found.tsx for graceful error degradation.
• Header/Footer: Updated global navigation components to reflect the new route structure.
• UI Components: integrated shadcn/ui components for consistent design system usage (Toast, Dialog, etc.).

🔗 Related Changes

• src/app/(auth)/: New Auth directory.
• src/app/providers.tsx: Global providers.
• src/app/layout.tsx: Root layout updates.
• src/services/auth-service.ts: Auth service refinements.