2b7495e4dc
New Settings -> Accounting tab (gated by the accounting flag) to edit the km rate, per-diem rate and the "require proof for expense" toggle (reads GET / writes PUT /admin/settings/accounting). Rates are CHF, stored as integer minor units; carries the "verify with your Treuhaender" disclaimer. Wired into SettingsPage (TabType, keys, flag-gated nav item, render) + the features barrel. i18n: settings.accounting.* (EN + DE, DE native). Verified: tsc --noEmit clean (0 errors); en/de JSON valid; npm run build green.