Add a safe, beginner-friendly SQL Injection learning lab (educational)

[Vibhasha-5]

Summary

Add a new, safe and isolated learning lab to teach beginners about SQL Injection concepts, detection, and mitigation — without providing exploit payloads or instructions for attacking live systems. The lab will be runnable locally (Docker) and include exercises, a small demo app that illustrates vulnerable patterns (non-executable examples), a safe implementation, a local progress tracker, and short trivia links as rewards.

Why

• Makes the repository more beginner-friendly and practical.
• Encourages learning defensive techniques instead of enabling attacks.
• Great Hacktoberfest contribution that’s easy to review and merge.

Acceptance criteria / checklist

1. sql-injection-lab/README.md added with quick start and safety notice.
2. Dockerfile + docker-compose that runs the lab locally and isolated.
3. app/vulnerable_app.py and app/safe_app.py present; vulnerable file uses only illustrative pseudocode/commented examples (no exploit execution).
4. Exercises written (conceptual, non-actionable) with links to OWASP / PortSwigger for further reading.
5. Local JSON tracker and trivia reward system implemented (no server required).
6. Smoke tests pass: container boots and endpoints respond OK.
7. CONTRIBUTING / LICENSE_NOTE updated to include ethics & usage constraint

[amandewatnitrr]

@Vibhasha-5 assigned to you

[Vibhasha-5]

@amandewatnitrr thank you for assigning it to me. i have created a PR #80 kindly check.