[Feat] Implement Enable 2FA Endpoint

[droffilc1]

Description

The application does not currently support enabling two-factor authentication (2FA) for users. Implement an endpoint to allow users to enable 2FA.

Acceptance Criteria

• Create an API endpoint: POST /api/v1/auth/enable-2fa
• The endpoint should:
  • Generate a 2FA secret key for the user.
  • Generate a QR code for authentication apps like Google Authenticator.
  • Store the 2FA secret securely in the database.
  • Require the user to verify 2FA setup by providing a valid one-time passcode (OTP).
  • Enable 2FA for the user upon successful verification.

Responses

✅ Success Response (200 OK)

{   "message": "2FA enabled successfully" }

📌 QR Code Response (200 OK - initial request before verification)

{   "message": "Scan the QR code to set up 2FA",   "qr_code": "data:image/png;base64,....",   "secret": "JBSWY3DPEHPK3PXP" }

❌ Error Responses

• Invalid OTP (400 Bad Request)

   {   "error": "Invalid OTP. Please try again." }

• 2FA Already Enabled (409 Conflict)

    {   "error": "2FA is already enabled for this account." }

• Unauthorized Request (401 Unauthorized)

    {   "error": "User not authenticated" }

Technical Notes

• Use Time-based One-Time Password (TOTP) for 2FA.
• Ensure proper error handling for invalid OTPs and edge cases.
• Follow the existing authentication structure in the project.