Extends the existing dark palette to cover the invoicing UI:
- .invoice-list: zebra-free table with right-aligned totals.
- .badge / .badge-pending / .badge-paid: small status chip.
- .items-table: per-row inputs for description/qty/unit price, .remove-row
button styling.
- .invoice-grid: two-column layout for the terms block (issued/due,
currency/GEL rate).
- .link-button: subdued "+ add line" affordance.
- .download-button: the prominent CTA on the public landing page.
- color-scheme: dark on date inputs so the native picker matches the
rest of the page.
No changes to existing rules.
