Feature/evaluation dashboard

[Prateek2007-cmd]

Description

implementing the Real-Time Evaluation Dashboard, allowing developers to visually benchmark recommendation model performance (Precision@K, Recall@K, NDCG@K) directly from the web interface.
Closes #1636
Changes included:

• Backend APIs: Added GET /api/evaluate and GET /api/evaluate/history endpoints to backend/main.py. These trigger real-time benchmarking and manage a rolling history of the last 20 evaluations.
• Evaluation Logic: Completed the run_evaluation stub in src/evaluation/evaluation.py. It now actively builds a test dataset, computes recommendations across all modes (Content, Collaborative, Sentiment, Hybrid), and calculates exact performance metrics.
• Frontend Integration: Hooked up the pre-built benchmarking.js UI by calling initBenchmarkingDashboard() on DOM load in frontend/app.js. The dashboard now correctly fetches from the new APIs, renders SVG bar charts comparing model performance, and populates the recent run history table.

Related Issues

• Resolves #1599

Type of Change

• New Feature (Real-time Evaluation Dashboard and API endpoints)

Testing

• Verified run_evaluation calculates correct metrics without ZeroDivisionErrors.
• Verified /api/evaluate correctly records and returns evaluation history.
• Confirmed the "Model Performance" UI panel renders correctly on the frontend and builds charts successfully upon clicking "Run Evaluation".

[github-actions]

🎉 Welcome to Hybrid Recommender, @Prateek2007-cmd! This is your first contribution here!

Labels added: gssoc:approved | mentor:leonagoel | status:review-needed

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