Add the ERPNext settings UI, History and detail controls, and voiced.invoice.v1 export (Phase F3)

- Settings gets an Integrations tab: connection fields with a write-only API secret, a CA PEM option, Test connection with versions and warnings, live mapping lists loaded after a test, naming mode, toggles and its own Save.
- Pushing for a GST-registered vendor is refused until a connection test result is stored. The UI shows the reason and disables Send.
- History shows an ERPNext status column from one bulk call, a row Send and Open in ERPNext, and a bulk Send selected with a draft-or-submit confirm step and per-row results that never abort the batch. The detail view gets an ERPNext panel and per-payment send. All of it is hidden or disabled when the integration is not configured.
- Optional auto-push after issue runs in the background and never blocks or fails the issue.
- Generic export: a deterministic voiced.invoice.v1 JSON (and CSV line items) for selected invoices, documented in docs/voiced-invoice-v1.md with a golden test. Money is integer paise plus a decimal string.

The new screens have not been run in a webview yet. The ERPNext Payment Entry deduction fields still need a live check.

src/views/NewInvoice.tsx

@@ -59,6 +59,7 @@ import { SHORTCUT_LIST, useShortcuts } from "../hooks/useShortcuts";
 import PageSetupControls from "../components/PageSetupControls";
 import { useInvoicePdf } from "../hooks/useInvoicePdf";
 import { useInvoiceExport } from "../hooks/useInvoiceExport";
+import { autoPushIssued } from "../lib/erpnextUi";
 import ExportButton, { ExportModePicker } from "../components/ExportButton";
 import ExportFeedback from "../components/ExportFeedback";
 import { createExportDeps } from "../lib/exportDeps";
@@ -649,6 +650,16 @@ export default function NewInvoice({ settings, onSettingsChange, active, onActiv
     detachDraft();
     api.listClients().then(setClients).catch(() => {});
     void refreshDrafts();
+    // "Send on issue": in the background, so it never delays or fails the issue; the result arrives as a toast.
+    void autoPushIssued(
+      { getConfig: api.erpnextGetConfig, push: api.erpnextPushInvoice },
+      outcome.invoice,
+      settings.gstRegistration !== "unregistered",
+    )
+      .then((note) => {
+        if (note) toast[note.kind](note.title, note.subtitle);
+      })
+      .catch(() => {});
     // Unarchived invoices export by rendering and archiving first (see exportInvoice), so this still works.
     await exp.start(outcome.invoice, mode, "original");
     setSaving(false);