feat(orders): PDF footer = issuer name+email, 'Zobrazit objednávku' button, per-currency list totals

- Issued-order PDF: drop the Vystavil/Schválil signature row; footer now shows
  'Vystavil: <name>' + 'E-mail: <email>' from the logged-in user (authData).
- IssuedOrderDetail PDF button 'Export PDF' -> 'Zobrazit objednávku' (already
  opens inline like invoices' 'Zobrazit fakturu').
- New /orders/stats + /issued-orders/stats endpoints sum order total (incl VAT)
  per currency across the active filter; rendered as 'Celkem: …' beneath both
  the received and issued lists. formatMultiCurrency lifted to a shared util.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/__tests__/issued-orders.test.ts

@@ -276,6 +276,8 @@ describe("renderIssuedOrderHtml", () => {
     },
   ];
 
+  const issuer = { name: "Jan Novák", email: "jan.novak@firma.cz" };
+
   it("renders the PO number, items, and both party names (PO direction)", () => {
     const html = renderIssuedOrderHtml(
       order,
@@ -283,6 +285,7 @@ describe("renderIssuedOrderHtml", () => {
       { name: "Dodavatel s.r.o." },
       { company_name: "Naše firma" },
       "cs",
+      issuer,
     );
     expect(html).toContain("26720001");
     expect(html).toContain("Materiál");
@@ -297,8 +300,28 @@ describe("renderIssuedOrderHtml", () => {
   });
 
   it("strips script tags from notes", () => {
-    const html = renderIssuedOrderHtml(order, items, null, null, "cs");
+    const html = renderIssuedOrderHtml(order, items, null, null, "cs", issuer);
     expect(html).not.toContain("<script>");
     expect(html).not.toContain("alert(1)");
   });
+
+  it("footer shows the logged-in user's name + e-mail, not the Schválil column", () => {
+    const html = renderIssuedOrderHtml(order, items, null, null, "cs", issuer);
+    // New footer: Vystavil <name> + E-mail <email> from authData.
+    expect(html).toContain("Jan Novák");
+    expect(html).toContain("jan.novak@firma.cz");
+    expect(html).toContain("E-mail:");
+    // The old two-column signature footer is gone.
+    expect(html).not.toContain("footer-row");
+    expect(html).not.toContain("Schválil:");
+  });
+
+  it("omits the e-mail line when the issuer has no e-mail", () => {
+    const html = renderIssuedOrderHtml(order, items, null, null, "cs", {
+      name: "Jan Novák",
+      email: "",
+    });
+    expect(html).toContain("Jan Novák");
+    expect(html).not.toContain("E-mail:");
+  });
 });