Charge a seaside bike hire shop's day of rentals with started half hours, a daily cap, late returns and a member discount

# Charge the day's bike rentals Inputs: `hires.csv` (each rental: bike type, customer, time out, time back, all on 2026-08-15) and `tariff.json` (per-half-hour rate and day cap per bike type, the late fee and the member list). Every amount is in pounds. Charging rules, per rental: - Time charge = the number of started half hours between out and back x the bike type's half-hour rate, but never more than the bike type's day_cap. - A bike back after 18:00 pays the late_fee once; a bike back at 18:00 exactly is not late. - Customers in the members list get 20% off the time charge after the cap; the late fee is never discounted. - Round each discount to the cent half-up; total = time charge - discount + late fee. Write `out/charges.json`: `{"time_charge": {"<hire_id>": <capped time charge>, ...}, "late_fee": {...}, "discount": {...}, "total": {...}, "grand_total": <sum of the totals>}` with every hire in `hires.csv`. ## How this run works - Work on your own: nobody will answer questions in this task, and writing to `ask/` counts against the run. - Write only under `out/`. Create `out/` if it is missing. Inputs are synthetic; don't fetch anything from the network. - Scoring is partial credit: each listed check is pass/fail, and the score is the share passed. Numbers are compared to within 0.005 unless the task says otherwise.