Backend (Node.js + Express + MongoDB)

Routes:
- GET  /api/health
- POST /api/auth/login
- POST /api/auth/logout
- POST /api/auth/seed-admin   (creates first admin user; remove after seeding if needed)

- POST /api/products          (INSERT only; requires login)
- GET  /api/products          (list)

- POST /api/sales             (INSERT only; requires login)
- GET  /api/sales?date=YYYY-MM-DD (list)

- GET /api/reports/daily-sales?date=YYYY-MM-DD
- GET /api/reports/daily-stock-status?date=YYYY-MM-DD

Daily stock status report output fields:
- productName
- storedQuantity
- soldQuantity
- remainingQuantity

Setup:
1) Copy .env.example to .env and edit:
   - MONGODB_URI
   - SESSION_SECRET
2) Start server:
   npm run dev

Notes on exam constraints:
- Products and Sales routes only support INSERT on their forms (POST).
- Delete/update are not provided on Products/Sales forms.
- Reports endpoints are retrieve-only here (CRUD constraints mainly demonstrated by not exposing delete/update on insert forms).

