Function generateAccessToken

generateAccessToken(payload: TokenPayload): string
Generate JWT access token for API authentication

Creates a short-lived JWT access token containing user identification and authorization information. The token is signed with the JWT_SECRET environment variable and includes standard JWT claims (issuer, audience, expiration) for security and validation.

Access tokens are designed for frequent API requests and have a short expiration time (default 15 minutes) to minimize security risks if compromised. They contain user ID, email, and role information needed for authentication and authorization middleware.
Parameters
- payload: TokenPayload
  User information to encode in the token containing userId, email, and role
Returns string
Signed JWT access token string
Throws
When JWT_SECRET environment variable is not configured
Example
```
// Generate access token for authenticated user
const payload = {
  userId: 'user-uuid-123',
  email: 'user@example.com',
  role: 'student'
};

const accessToken = generateAccessToken(payload);
// Returns: 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...'
```
Example
```
// Token contains standard JWT structure
// Header: { "alg": "HS256", "typ": "JWT" }
// Payload: { 
//   "sub": "user-uuid-123", 
//   "email": "user@example.com", 
//   "role": "student",
//   "iss": "wayrapp-api",
//   "aud": "wayrapp-client",
//   "iat": 1234567890,
//   "exp": 1234568790
// }
```
- Defined in src/shared/utils/auth.ts:160