feat(frontend): implement Next.js frontend package foundation with complete API integration

This commit establishes the complete Next.js frontend foundation with comprehensive backend integration:

## Core Infrastructure ✅
- Next.js 14 with App Router and TypeScript configuration
- Tailwind CSS with custom design system and dark mode
- Complete project structure with proper imports and path aliases

## API Integration Layer ✅
- Full-featured API client with authentication, file upload, and WebSocket
- Comprehensive TypeScript type definitions for all API responses
- Axios-based HTTP client with interceptors and error handling
- Socket.io integration for real-time progress updates

## Authentication System ✅
- useAuth hook with Google OAuth integration
- JWT token management with automatic refresh
- Protected route handling and session persistence
- Login/logout flow with redirect management

## File Upload System ✅
- useUpload hook with drag & drop functionality
- File validation (size, type, duplicates)
- Progress tracking during upload
- Batch creation and image processing workflow

## WebSocket Integration ✅
- useWebSocket hook for real-time updates
- Progress subscription for batch processing
- Reconnection logic with exponential backoff
- Event-driven updates for batches, images, and user data

## UI Foundation ✅
- Responsive Header with user authentication state
- Professional Footer with proper navigation
- Error Boundary for graceful error handling
- Toast notification system with multiple variants
- Loading spinners and UI components

## Layout & Navigation ✅
- Main page component with authenticated/unauthenticated states
- Dynamic content switching between landing and dashboard
- Mobile-responsive design with proper accessibility

This provides the complete foundation for a production-ready frontend that integrates seamlessly with the existing backend APIs, supporting all core workflows from authentication to file processing.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

packages/frontend/tsconfig.json

@@ -0,0 +1,49 @@
+{
+  "compilerOptions": {
+    "target": "ES2020",
+    "lib": ["dom", "dom.iterable", "es6"],
+    "allowJs": true,
+    "skipLibCheck": true,
+    "strict": true,
+    "noEmit": true,
+    "esModuleInterop": true,
+    "module": "esnext",
+    "moduleResolution": "bundler",
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "jsx": "preserve",
+    "incremental": true,
+    "plugins": [
+      {
+        "name": "next"
+      }
+    ],
+    "baseUrl": ".",
+    "paths": {
+      "@/*": ["./src/*"],
+      "@/components/*": ["./src/components/*"],
+      "@/hooks/*": ["./src/hooks/*"],
+      "@/lib/*": ["./src/lib/*"],
+      "@/types/*": ["./src/types/*"],
+      "@/utils/*": ["./src/utils/*"],
+      "@/store/*": ["./src/store/*"]
+    },
+    "forceConsistentCasingInFileNames": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true,
+    "noUncheckedIndexedAccess": true,
+    "exactOptionalPropertyTypes": true
+  },
+  "include": [
+    "next-env.d.ts",
+    "**/*.ts",
+    "**/*.tsx",
+    ".next/types/**/*.ts"
+  ],
+  "exclude": [
+    "node_modules",
+    ".next",
+    "out",
+    "dist"
+  ]
+}