source/
├── app/                    # Next.js App Router pages
│   ├── auth/login/        # Authentication pages
│   ├── dashboard/         # Main dashboard
│   ├── employees/         # Employee management
│   ├── recruitment/       # Recruitment module
│   ├── payroll/          # Payroll management
│   ├── attendance/       # Attendance tracking
│   ├── calendar/         # Events calendar
│   ├── documents/        # Document management
│   ├── reports/          # Reporting module
│   └── settings/         # Application settings
├── components/           # Reusable UI components
│   ├── ui/              # Base UI components (buttons, inputs, etc.)
│   ├── sidebar.tsx      # Navigation sidebar
│   └── header.tsx       # Top header bar
├── lib/                 # Utility libraries
│   ├── auth.ts         # Authentication utilities
│   └── api.ts          # API client and types
└── package.json        # Project dependencies

export interface AuthSession {
  token: string
  user: {
    id: number
    name: string
    email: string
  }
}

const SESSION_KEY = 'hcmatrix_session'

export const auth = {
  saveSession(session: AuthSession): void,
  getSession(): AuthSession | null,
  clearSession(): void,
  isAuthenticated(): boolean,
  getToken(): string | null
}

async function apiCall<T>(
  endpoint: string,
  method: 'GET' | 'POST' = 'GET',
  body?: Record<string, unknown>,
  token?: string
): Promise<T> {
  const url = `${PROXY_BASE}${endpoint}`
  
  const headers: HeadersInit = {
    'Accept': 'application/json',
  }
  
  if (token) {
    headers['Authorization'] = `Bearer ${token}`
  }
  
  // API request implementation...
}