Sailing regatta series scoring with codes, dead heats, redress, discards and tie-breaks

# Sailing regatta series scoring (low-point system) `input.json` (synthetic) has `entries` (`sail`), `races` (each with `finishes` in finishing order), `discards` ({"min races": discards}), and `penalty_pct`. Write `solve.py` (Python 3 standard library only); `python solve.py input.json answer.json` writes `answer.json` and `results.html`. Fresh series are generated. ## Rules (N = number of entries) 1. A finish item is `{"sail": s}` or `{"sail": [s1, s2, ...]}` (a dead heat), with optional `code` (case-insensitive) and `points`. Sails not in `entries` are ignored. A boat already seen in that race is ignored (only its first item counts). 2. Codes DNC, DNS, OCS, DNF, RET, DSQ, DNE, UFD, BFD score **N + 1** and do **not** take a finishing place (boats behind move up). 3. Other boats take places 1, 2, 3, ... in item order; a dead heat of k boats takes the next k places and each scores their average (e.g. 2.5). 4. ZFP and SCP: place points + round_half_up(N * penalty_pct / 100), capped at N + 1. DPI: place points + `points`, capped at N + 1. 5. RDG with `points`: that score. RDG without `points`: the average of that boat's scores in all other races, excluding its other averaged-RDG races, rounded half-up to 1 decimal; N + 1 if there are none. 6. An entry missing from a race's items scores N + 1 with code DNC. A boat's code for a race is the upper-cased code (`""` if none). 7. Discards: d = the value for the largest key k with races sailed >= k (0 if none). Exclude the boat's d worst scores, never a DNE score; among equal scores exclude the later race first. `total` = sum of all scores; `net` = total - excluded. 8. Ranking: lower net first. Ties: (A8.1) compare each boat's non-excluded scores sorted best to worst, first difference wins; (A8.2) then compare scores in the last race, then the race before, and so on (excluded scores included). Still tied: entry order. ## Visual output: results.html A static, self-contained page (no `<script>`, `<img>`, `<link>`, `<iframe>`/`<object>`/`<embed>`, `on*` handlers, external URLs, CSS url(http)/@import or fetches; renders headless) with `<table id="results">` and one `<tr id="row-<sail>">` per boat, **in rank order**. Layout and styling are not graded. ## answer.json `{"boats": {sail: {"points": [per race], "codes": [per race], "discarded": [0-based race indices, ascending], "total", "net", "rank"}}, "order": [sails in rank order], "discards_applied": d}` ## Scoring Hidden checks (partial credit; all must pass; numbers within 0.001): `codes_and_dnc`, `race_points_incl_ties_penalties`, `discards_and_totals`, `ranking_with_tiebreaks`, `results_html_static` (exists, static rules, ids, row order) on the given series; `fresh_run_1`, `fresh_run_2`. 30-second limit per run.