[FTR] Images, First & Last name, User-Events table

[BojanaAri]

This PR extends the user model with the following attributes: First name, Last name, Profile picture.
In addition to handle attendance, I added a user-events many-to-many table that has an additional attribute for attendance status (interested, going, cancelled, attended);

Changes:

• Profile Update Endpoint PUT /api/profile/update. Validates username uniqueness, name format, and profile picture constraints (10MB max, image-only, and only const ALLOWED_FIELDS = ['username', 'firstName', 'lastName', 'profilePicture'];)
  • Input Sanitization: removes dangerous characters and normalizes user inputs (trim, lowercase)
  • File Upload Security: Type, size, and existence validation for profile pictures integrated with Strapi's upload plugin
• Error Handling: Early returns with appropriate HTTP status codes (400 for validation, 500 for system errors)