Feat: Add JD matching logic for required skills

[Atharv094]

Closes: #18
## 📝 Description

This PR implements Job Description (JD) matching for the AI Resume Analyzer.

Previously, the backend ignored the submitted job_description field and
matched the resume against generic hardcoded roles. Now, if a user pastes a job
description on the frontend, the backend dynamically extracts required skills
from that JD text and compares the resume strictly against those skills to
generate an accurate match percentage and missing keywords list.

## 🔗 Related Issue

Closes #18

## ✅ Type of Change

- [ ] 🐞 Bug fix (non-breaking change that fixes an issue)
- [x] ✨ New feature (non-breaking change that adds functionality)
- [ ] 📚 Documentation update
- [ ] 💅 UI/UX improvement
- [ ] ♻️ Refactor (no functional change)
- [ ] ⚡ Performance improvement

## 🧪 How Has This Been Tested?

- [x] Frontend builds (`npm run build`) and lints (`npm run lint`) clean
- [ ] Backend tests pass (`python manage.py test analyzer`)
- [x] Manually tested in the browser / API client

## 📋 Checklist

- [x] My code follows the project's style and conventions
- [x] I have linked the related issue above
- [x] I have read the [Code of Conduct](CODE_OF_CONDUCT.md)

[vercel]

@Atharv094 is attempting to deploy a commit to the a2521729-9889's projects Team on Vercel.

A member of the Team first needs to authorize it.

[Muskankr]

@Atharv094 , resolve conflicts

[Atharv094]

@Muskankr I will solve the conflicts asap please don't unassign