Add payments with TDS, invoice detail view and filterable History (Phase E2)

- Migration M8 adds payments (cash, TDS, mode, reference). Payment status is derived, never stored: unpaid, partially paid, paid, or overdue. Overpayment is rejected, TDS counts toward settling, and only issued invoices accept payments. list_invoices and get_invoice carry the paid, TDS and balance summary.
- New invoice detail view: archived-PDF preview, payments list, Record payment modal, Export, Duplicate (as a draft), Re-render and Cancel. An invoice with payments cannot be cancelled until they are deleted.
- History gets search, status, financial-year, month and client filters, sortable columns, pagination, footer totals and an FY summary. Cancelled invoices are excluded from totals. The per-row archive-status calls are gone; archiving is on the detail page.
- Rust tests for payments and the list summary; vitest for fiscal-year, money, filter and duplicate helpers.

PDF output and fingerprint goldens are unchanged. The new UI has not been run in a webview yet.

src/styles/carbon.scss

@@ -540,3 +540,133 @@ body {
   margin-top: 0.5rem;
   font-size: 0.75rem;
 }
+
+/* ---------- Invoice history and detail ---------- */
+.voiced-num {
+  text-align: right;
+}
+
+.voiced-history__fy {
+  font-size: 1.25rem;
+  font-weight: 400;
+  margin-bottom: 0.5rem;
+}
+
+.voiced-history__tiles,
+.voiced-detail__tiles {
+  display: grid;
+  grid-template-columns: repeat(auto-fit, minmax(10rem, 1fr));
+  gap: 1rem;
+  margin-bottom: 1.5rem;
+}
+
+.voiced-history__amount,
+.voiced-detail__amount {
+  font-size: 1.75rem;
+  font-weight: 400;
+}
+
+.voiced-history__tile--overdue {
+  border-left: 4px solid var(--cds-support-error);
+}
+
+.voiced-history__filters {
+  display: grid;
+  grid-template-columns: minmax(14rem, 2fr) repeat(4, minmax(9rem, 1fr)) auto;
+  gap: 1rem;
+  align-items: end;
+  margin-bottom: 1rem;
+}
+
+.voiced-history__row {
+  cursor: pointer;
+}
+
+.voiced-history__totals {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.5rem 2rem;
+  padding: 0.75rem 1rem;
+  background: var(--cds-layer-accent);
+  border-top: 1px solid var(--cds-border-subtle);
+}
+
+.voiced-detail__head {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 0.75rem;
+  margin-top: 1rem;
+}
+
+.voiced-detail__actions {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 0.5rem;
+  margin: 1rem 0;
+}
+
+.voiced-detail__grid {
+  display: grid;
+  grid-template-columns: minmax(0, 3fr) minmax(0, 2fr);
+  gap: 2rem;
+  align-items: start;
+}
+
+@media (max-width: 1100px) {
+  .voiced-detail__grid,
+  .voiced-history__filters {
+    grid-template-columns: 1fr;
+  }
+}
+
+.voiced-detail__h2 {
+  font-size: 1.25rem;
+  font-weight: 400;
+  margin-bottom: 0.75rem;
+}
+
+.voiced-detail__parties {
+  display: grid;
+  grid-template-columns: 1fr 1fr;
+  gap: 2rem;
+}
+
+.voiced-detail__field {
+  margin-bottom: 0.75rem;
+}
+
+.voiced-detail__pre {
+  white-space: pre-line;
+}
+
+.voiced-detail__totals {
+  margin: 1rem 0 0.5rem auto;
+  max-width: 22rem;
+}
+
+.voiced-detail__totals > div {
+  display: flex;
+  justify-content: space-between;
+  padding: 0.25rem 0;
+}
+
+.voiced-detail__grand {
+  border-top: 1px solid var(--cds-border-strong);
+  font-weight: 600;
+}
+
+.voiced-detail__preview {
+  position: sticky;
+  top: 4rem;
+}
+
+.voiced-detail__unarchived {
+  padding: 1.5rem;
+  background: var(--cds-layer-accent);
+}
+
+.voiced-detail__unarchived p {
+  margin-bottom: 1rem;
+}