Implement MFA Verification via Email

[uzayisinalici]

Description

Key Features:

• After successful username and password verification, a 6-digit MFA code is sent to the user's registered email.
• The user must enter this code to complete the login process and access the dashboard.
• Invalid or expired codes result in error messages.
• Credentials and email settings are managed via .env for security.

Security Benefits:

• Reduces risk from password leaks or brute-force attacks.
• Ensures only verified users can access sensitive areas like the dashboard.

Tests:

• Added unit tests for both successful and failed MFA verification scenarios.

Fixes # (issue)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a user documentation update
• This change requires a container update
• This change is dependent on other pull requests

Checklist:

• Code formatting standard applied
• I have performed a self-review of my code
• Code commented and documented
• New and existing unit tests pass locally with my changes