Charge a pottery studio's members for a week of kiln firings and flag overloaded kilns

# Charge a pottery studio's members for a week of kiln firings and flag overloaded kilns Inputs: `kilns.csv` (kiln_id, name, shelf_cm2), `members.csv` (member_id, name), `glazes.csv` (glaze), `firings.csv` (firing_id, kiln_id, date, kind, status), `pieces.csv` (piece_id, member_id, firing_id, footprint_cm2, glaze) and `rates.json` (bisque_per_cm2, glaze_per_cm2, minimum_charge). All members, kilns, glazes and pieces are synthetic; prices are in dollars. These rules are the studio's; where `studio-notes.txt` disagrees, the rules win. Rules: - Firings: a firing with status `fired` happened. A firing with status `aborted` was stopped by a kiln fault; its pieces are refired later at the studio's cost, so they are not charged and count nowhere in this week's figures. - Charges: each piece in a fired firing is charged footprint_cm2 × the rate for the firing's kind (bisque_per_cm2 for `bisque`, glaze_per_cm2 for `glaze`), but never less than minimum_charge: a piece whose rate charge is below minimum_charge is charged minimum_charge instead. Don't round until the output. - Overloads: a fired firing is overloaded when the total footprint_cm2 of its pieces is more than its kiln's shelf_cm2. A firing that fills the shelf exactly is not overloaded. - Glazes: a piece counts under its glaze only when it was in a fired `glaze` firing (bisque pieces have no glaze yet). - Kilns: a kiln's firing count is the number of its fired firings. - Write `out/kiln-ledger.json`: `{"overloaded_firings": [<sorted firing_ids>], "charged_total": <dollars>, "charges_by_member": {"<member_id>": <dollars>, ...}, "glazed_pieces_by_glaze": {"<glaze>": <count>, ...}, "fired_count_by_kiln": {"<kiln_id>": <count>, ...}}`. - Roll-ups: In charges_by_member, members in members.csv with no charged pieces are left out. In glazed_pieces_by_glaze, glazes in glazes.csv with no pieces in a fired glaze firing are left out. In fired_count_by_kiln, kilns in kilns.csv with no fired firings are left out. ## 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.