Adds POST /api/cashup/:id/unfinalise (admin-only) to revert a
finalised cash up back to draft so it can be corrected, plus an
Unfinalise button in the history table for admin users.
- History: slice session_date to YYYY-MM-DD before Date parse (postgres
returns date columns as ISO timestamps in JSON)
- History: fix Edit/View navigate link passing full ISO string as date param
- Weekly report: add daily status row, reconciliation variance (banked vs
Newbook reported), sales with gross+net, debtors/creditors lazy-loaded
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>