Add NOTEBOOK_REVIEW.md with structured review for AI_project.ipynb

[Anushka-Verma-CODES]

Motivation

• Provide a concise, actionable review of AI_project.ipynb that documents strengths, identifies methodological and reproducibility risks, and prioritizes remediation steps to improve model quality.

Description

• Add NOTEBOOK_REVIEW.md containing an overall assessment, what is working well, key issues (including LabelEncoder misuse, temporal leakage from random splits, incomplete modeling workflow, Colab path reproducibility, and missing feature engineering), prioritized recommendations (e.g., use OneHotEncoder/ColumnTransformer, time-aware splits, baseline + tree models), and a quick scorecard.

Testing

• Validated by loading the notebook with a Python script to inspect cell count and content (python -c ...), printing the new review file (nl -ba NOTEBOOK_REVIEW.md | sed -n '1,220p'), and committing the file to git with git add/git commit, all of which completed successfully.

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Codex Task