Move VAT-code CRUD and the rate→code / treatment→code maps off the
Chart-of-accounts page into a self-contained VatCodesManager rendered in
Settings → Accounting, so all VAT config lives in one place. CoA keeps
the accounts table, default/system accounts, and expense-category maps.
Both pages save disjoint key sets through the partial-merge updateSettings
(CoA → account keys only; VatCodesManager → ledger_vat_map +
ledger_output_vat_map only), so neither reverts the other's edits.
Luca
4ff5b84cb6