Strip a leading UTF-8 BOM before parsing rule CSVs (it was causing the
header row to be misread as a rule) and skip rows that clearly failed
CSV parsing (e.g. a whole line landing in the rule_number field after
a spreadsheet app double-encoded a quoted cell) instead of silently
loading garbage.
Add PUT /api/rules/{lang}/{number} and GET /api/rules/numbers so rule
text, suggested penalty and escalation mode can be edited per language
from the admin UI, always writing the CSV back out with correct
quoting via encoding/csv. Also fixes two bugs found while wiring this
up: rulesDir() ignored the configured rules_dir (falling back to a
RULES_DIR env var that's never set), and the CORS middleware didn't
allow PUT.