Enhancement: Add customizable challenges and competitions

[anshul23102]

Problem Statement

Limited challenges:

• Predefined challenges only
• No custom challenges
• Limited replayability

Business Impact: Low engagement
Technical Impact: No challenge engine

Root Cause Analysis

Challenges hardcoded.

Solution Overview

1. Creation: create custom challenges
2. Rules: define challenge rules
3. Scoring: custom scoring
4. Competitions: run competitions
5. Sharing: share challenges

Type of Change

• Feature: Custom challenges

Testing Done

• Creation test: works
• Scoring test: correct
• Competition test: runs

Related Issue

Relates to engagement

Suggested Labels

feature, challenges, engagement, gssoc26

[github-actions]

Thank you for raising this issue!

We'll review it as soon as possible. We truly appreciate your contributions! ✨

Meanwhile make sure you've visited the README.md, CONTRIBUTING.md, and CODE_OF_CONDUCT.md before creating a PR for this. Also, please do NOT create a PR until this issue has been assigned to you. 😊