Add "BALANCED" Gamification Badge to User Profile

[jagdish-15]

We are expanding the gamification system on user profiles! We need to implement a new "BALANCED" badge that unlocks dynamically based on a user's progress.

Badge Name: [BALANCED]

Unlock Condition: The user has solved at least 5 Easy, Medium, and Hard problems, and the difference between the highest and lowest solved counts is no more than 5% of the highest solved count.

Implementation Steps

This is a purely frontend feature. All logic belongs in frontend/js/user/badges.js and CSS styling in frontend/user.html.

1. Add the badge object to the ALL_BADGES array.
2. Write the evaluation logic inside the loadBadges() function to check the user's history data. If the condition is met, add the ID to the earnedSet.
3. Add a visually distinct CSS class (e.g. teal/cyan gradient theme) for the badge in frontend/user.html.

[Yashaswini-K-P]

i would like to work on this