Add functions for parsing ML results and building Parquet files

[AbhirupaGhosh]

Description

This file contains functions to parse machine learning result files into structured metadata and to build Parquet files from various ML performance and feature datasets.

Model Performance and Top Features Summary

Model type	Performance file	Top features file
Single-drug/class model	all_perf.parquet	all_top_features.parquet
Leave-One-Drug-Out (LODO)	LOO_drug_perf.parquet	LOO_drug_top_features.parquet
Cross-drug test	cross_drug_perf.parquet	—
Geographically stratified model	country_perf.parquet	country_top_features.parquet
Leave-One-Geography-Out (LOGO)	LOO_country_perf.parquet	LOO_country_top_features.parquet
Cross-geography test	cross_country_perf.parquet	—
Time-stratified model	year_perf.parquet	year_top_features.parquet
Leave-One-Time-Period-Out (LOTO)	LOO_year_perf.parquet	LOO_year_top_features.parquet
Cross-time test	cross_year_perf.parquet	—
Multiclass MDR model	MDR_perf.parquet	MDR_top_features.parquet

What kind of change(s) are included?

• Feature (adds or updates new capabilities)
• Bug fix (fixes an issue).
• Enhancement (adds functionality).
• Breaking change (these changes would cause existing functionality to not work as expected).

Checklist

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• I have read and followed the CONTRIBUTING.md guidelines.
• I have searched for existing content to ensure this is not a duplicate.
• I have performed a self-review of these additions (including spelling, grammar, and related).
• I have added comments to my code to help provide understanding.
• I have added a test which covers the code changes found within this PR.
• I have deleted all non-relevant text in this pull request template.
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[amcim]

I am going to test this code in a staging branch with PR #8 . Once that PR is approved, this will be able to be approved instantly after that

[amcim]

Approved for merge because tested with a staging branch along with PR #8. See comments in PR #8 for notes on the approval of this branch