Rules & VR

When VR changes the rules from a date, add a new version with that effective-from date (a future date — the current version stays in force until then). Use the version picker to see the numbers from any period, past or scheduled. Only super admins can change rules, and the latest version can be removed to undo a mistake.
Vacation already accrued in completed months is frozen and never rewritten — a change only affects the current month onward.