Apportion a building's quarterly service charge with non-recoverable costs, a mid-quarter tenant change, a vacant unit and capped leases

# Apportion the Q3 service charge across tenants Inputs: `costs.csv` (the building's Q3 2026 costs), `units.csv` (every unit and its floor area), `leases.csv` (leases, with start and end dates and optional caps) and `apportionment.json`. Work out each lease's service charge for the quarter. - Only recoverable costs go into the pool: leave out every category listed in `non_recoverable_categories` (match ignoring letter case). - Tenant share = pool x (unit area x days the lease was in force in the quarter) / (total area of all units x days in the quarter). - A lease is in force from its start date to its end date, both days included; a blank end date means it continues. - If a lease has a `cap_per_quarter`, the tenant pays the lower of its share and the cap. - The landlord bears vacant space and anything above a cap: landlord_share = pool minus the sum of the rounded tenant charges. - Round each charge to cents half-up only at the end. Write `out/service-charges.json`: `{"recoverable_total": <pool>, "charges": {"<lease_id>": <charge>, ... every lease in force for at least one day of the quarter}, "landlord_share": <amount>}`. ## 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.