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/components/RecordPaymentModal.tsx

@@ -0,0 +1,127 @@
+import { useEffect, useState } from "react";
+import { InlineNotification, Modal, Select, SelectItem, TextInput } from "@carbon/react";
+import { api } from "../lib/api";
+import { todayIst } from "../lib/fiscal";
+import { formatPaise, paiseToInput, parseRupeesToPaise } from "../lib/money";
+import { PAYMENT_MODES, type Payment, type PaymentMode } from "../lib/payments";
+import { useReturnFocus } from "../hooks/useReturnFocus";
+
+interface Props {
+  open: boolean;
+  invoiceId: number;
+  invoiceNumber: string;
+  /** What is still owed, in paise. */
+  balancePaise: number;
+  onClose: () => void;
+  onRecorded: (payment: Payment) => void;
+}
+
+/** "Record payment": cash received plus TDS deducted, validated against the balance before it is sent. */
+export default function RecordPaymentModal({ open, invoiceId, invoiceNumber, balancePaise, onClose, onRecorded }: Props) {
+  const [paidOn, setPaidOn] = useState(todayIst());
+  const [amount, setAmount] = useState("");
+  const [tds, setTds] = useState("");
+  const [mode, setMode] = useState<PaymentMode>("bank_transfer");
+  const [reference, setReference] = useState("");
+  const [notes, setNotes] = useState("");
+  const [error, setError] = useState<string | null>(null);
+  const [busy, setBusy] = useState(false);
+  useReturnFocus(open);
+
+  // Each opening starts from the balance, so the common case (paid in full) is one click.
+  useEffect(() => {
+    if (!open) return;
+    setPaidOn(todayIst());
+    setAmount(paiseToInput(balancePaise));
+    setTds("");
+    setMode("bank_transfer");
+    setReference("");
+    setNotes("");
+    setError(null);
+    setBusy(false);
+  }, [open, balancePaise]);
+
+  const amountPaise = parseRupeesToPaise(amount);
+  const tdsPaise = parseRupeesToPaise(tds);
+  const amountInvalid = amountPaise === null;
+  const tdsInvalid = tdsPaise === null;
+  const total = (amountPaise ?? 0) + (tdsPaise ?? 0);
+  const overBalance = !amountInvalid && !tdsInvalid && total > balancePaise;
+  const empty = !amountInvalid && !tdsInvalid && total === 0;
+  const dateInvalid = !/^\d{4}-\d{2}-\d{2}$/.test(paidOn);
+  const canSubmit = !busy && !amountInvalid && !tdsInvalid && !overBalance && !empty && !dateInvalid;
+
+  const submit = async () => {
+    if (!canSubmit || amountPaise === null || tdsPaise === null) return;
+    setBusy(true);
+    setError(null);
+    try {
+      const payment = await api.recordPayment({ invoiceId, paidOn, amountPaise, tdsPaise, mode, reference, notes });
+      onRecorded(payment);
+    } catch (e) {
+      setError(String(e));
+      setBusy(false);
+    }
+  };
+
+  return (
+    <Modal
+      open={open}
+      modalHeading={`Record payment for ${invoiceNumber}`}
+      primaryButtonText={busy ? "Saving…" : "Record payment"}
+      secondaryButtonText="Cancel"
+      primaryButtonDisabled={!canSubmit}
+      onRequestClose={onClose}
+      onRequestSubmit={() => void submit()}
+    >
+      <div className="voiced-stack">
+        <p>
+          Balance due: <strong>{formatPaise(balancePaise)}</strong>
+        </p>
+        {error ? <InlineNotification kind="error" lowContrast hideCloseButton title="Could not record the payment" subtitle={error} /> : null}
+        <TextInput
+          id="payDate"
+          type="date"
+          labelText="Date received"
+          value={paidOn}
+          invalid={dateInvalid}
+          invalidText="Enter a date"
+          onChange={(e) => setPaidOn(e.target.value)}
+        />
+        <TextInput
+          id="payAmount"
+          inputMode="decimal"
+          labelText="Amount received (₹)"
+          helperText="Cash that reached your account"
+          value={amount}
+          invalid={amountInvalid || overBalance || empty}
+          invalidText={
+            amountInvalid
+              ? "Enter an amount like 1250.50"
+              : overBalance
+                ? `Amount plus TDS is more than the balance of ${formatPaise(balancePaise)}`
+                : "Enter an amount received or TDS deducted"
+          }
+          onChange={(e) => setAmount(e.target.value)}
+        />
+        <TextInput
+          id="payTds"
+          inputMode="decimal"
+          labelText="TDS deducted by client (₹)"
+          helperText="Counts towards settling the invoice; leave empty if none"
+          value={tds}
+          invalid={tdsInvalid}
+          invalidText="Enter an amount like 125.00"
+          onChange={(e) => setTds(e.target.value)}
+        />
+        <Select id="payMode" labelText="Mode" value={mode} onChange={(e) => setMode(e.target.value as PaymentMode)}>
+          {PAYMENT_MODES.map((m) => (
+            <SelectItem key={m.id} value={m.id} text={m.label} />
+          ))}
+        </Select>
+        <TextInput id="payRef" labelText="UTR / cheque number (optional)" value={reference} onChange={(e) => setReference(e.target.value)} />
+        <TextInput id="payNotes" labelText="Notes (optional)" value={notes} onChange={(e) => setNotes(e.target.value)} />
+      </div>
+    </Modal>
+  );
+}