feat: normalize ridership xlsx to JSON

[srinathn07]

Summary

Adds a standalone Python script that reads the monthly route ridership .xlsx file, normalizes it into a clean DataFrame, and exports JSON matching the shared contract.

Changes

• scripts/normalize_ridership.py — normalization script
• scripts/MonthlyRouteRidership_07_01_2025-07_31_2025.xlsx — sample data file

Output

• 54 rows across 20 routes and 3 day types (weekday, saturday, sunday)
• 9 normalized columns: route_number, route_name, day_type, schedule_id, monthly_ridership_upt, monthly_pass_miles_pmt, avg_trip_length_ptl, monthly_revenue_miles, monthly_revenue_hours
• JSON exported alongside the input file

[pau1davis]

Looks good!