Bill a clinic's visits with bundled codes, modifiers, a multiple-procedure discount and a sliding fee scale

# Bill a clinic's visits with bundling, modifiers, a multiple-procedure discount and a sliding fee scale Inputs: `visits.csv` (line_id, patient_id, date, code, units, modifier), `fee-schedule.json` (codes with fee and group, bundle pairs), `patients.csv` (patient_id, household_size, annual_income) and `sliding-scale.json`. All patients are synthetic test records; amounts are in dollars. `fee-schedule.json`, `sliding-scale.json` and these rules are the record; where `billing-note.txt` disagrees, the rules win. Rules: - A visit is one patient on one date. A line's full charge is fee × units; modifier 52 (reduced service) halves it. - Bundling: a line whose code is the child in a bundle pair is not billed (charge 0) when the same visit also has a line with the parent code, unless the child line has modifier 59. - Multiple-procedure discount: within a visit, billed lines whose code is in group procedure are ranked by full charge (after modifier 52), highest first, ties by the number in line_id; the first is charged 100% and every other one 50%. Each line's charge is rounded half-up to the cent. - Sliding scale: a patient's poverty-line percentage is annual_income / (base + per_person × (household_size − 1)) × 100. The discount is the pct of the first band whose max_pct is at least that percentage (max_pct null is the last band). It applies to each visit's gross (the sum of its line charges), rounded half-up to the cent; due = gross − discount. - Write `out/bill.json`: `{"lines": {"<line_id>": <charge>, ...}, "visits": {"<patient_id>|<date>": {"gross": <dollars>, "discount": <dollars>, "due": <dollars>}, ...}, "patients": {"<patient_id>": <sum of due>, ...}}`. ## 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.