toISOString() returns UTC — in BST (UTC+1) dates computed from new Date()
land one day early. Replace with local date components via fmt()/localStr().
Affects Weekly, Monthly, Rolling12Weeks, Rolling12Months.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Full wage cost reporting app — weekly/monthly views, rolling 12-week/12-month
history, budget management, Workforce API sync with SSE backfill, net sales
via forecasting public API, department filter, CSV export.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>