Added Suggestions for UserName if already in DB

Features

Responsive Signup Form:
- Input fields for username, email, password, and confirm password.
- Reusable components like Card, Button, and Input for consistent UI.
- Dynamic feedback with a loading spinner during submission.
Client-Side Validation:
- Enforced strong password requirements (uppercase letters, special symbols, and minimum length).
- Checked for valid email formats.
- Required a minimum username length of 3 characters.
Error Handling:
- Descriptive error messages for validation and server-side errors.
- Highlighted unavailable usernames and provided suggestions.
Dynamic Username Suggestions:
- Displayed up to 3 alternative usernames when the chosen one is taken.
- Allowed users to click suggestions to auto-fill the username field.

API Endpoint for Signup:
- Validates input on the server side for username, email, and password.
- Checks the database for existing usernames and emails.
- Generates non-conflicting, unique username suggestions.
Database Integration:
- MongoDB database connected via Mongoose.
- Efficient username and email duplication checks.
Security Enhancements:
- Passwords are encrypted using bcrypt before being stored.
Error Response:
- Meaningful messages with dynamic username suggestions if the entered username is unavailable.

Dynamic Username Suggestions:
- Ensures suggestions are unique and not already taken.
- Provides up to 3 alternative usernames dynamically.
User Feedback:
- Real-time validation feedback for a better user experience.
Scalable Architecture:
- Modular and extensible codebase for future improvements.
Code Documentation:
- Clean and detailed comments with docstrings for maintainability.