fix: resolve all 28 findings from the 2026-06-12 full audit (TDD-pinned)

Critical (data integrity):
- warehouse inventory confirm: throw (not return) inside $transaction so a
  failed deficit line rolls back the surplus corrective receipt — retries
  no longer accumulate phantom stock
- warehouse issue confirm: validate batches against the COMBINED quantity
  of all lines (duplicate FIFO-resolved lines drove batches negative)
- attendance delete: restore vacation_used/sick_used for the deleted day
  (in-transaction, clamped at 0)

High:
- auth refresh: terminated sessions (replaced_at only) get a plain 401 —
  the theft branch (family revocation) now fires only on replaced_by_hash
- POST /users strips role_id for non-admin callers (mirrors PUT guard)
- issued-order transition flushes unsaved edits via the full save payload
  when dirty; server contract (items+status in one PUT) pinned
- received-invoices list: usePaginatedQuery + pager (rows 26+ unreachable)
- received-invoice dates: nullableIsoDateString + NaN guard before NAS save
  (Czech-format dates corrupted month/year, orphaned NAS files)
- leave approval skips Czech public holidays and books each calendar year's
  hours against its own balance (mirrors createLeave)

Medium/Low (classes):
- 52 Zod caps aligned to DB column widths across 7 schemas (over-cap input
  500ed at Prisma instead of a Czech 400)
- FK pre-validation: projects update + warehouse receipts/issues return
  Czech 400s instead of P2003 500s
- invoice PDF degrades gracefully when the CNB rate is unavailable
  (recap omitted instead of 500 + lost NAS archival)
- date boundaries: local-day filters (warehouse lists/reports, audit-log),
  @db.Date coercion on invoice dates
- plan updateEntry re-checks the per-cell cap (self-excluding)
- {id} tiebreaks on customers/received-invoices/warehouse-items sorts;
  /items honors the client sort param
- htmlToPdf relaunches once when the shared browser died mid-render
- offer number release parses the year from the document number (cross-year
  finalize+delete left permanent sequence gaps)
- trips/vehicles km fields integer-coerced; AI budget regated to
  settings.company|settings.system; Settings System tab no longer clobbers
  Firma numbering patterns; draft invoices hide the dead PDF button;
  dashboard quick-trip invalidates ["vehicles"]; TOTP secret cap 64;
  audit-log + invoice month buckets day-shift fixes

Docs: corrected the stale "Chromium has no CSS margin-box footers" claim
(html-to-pdf.ts + CLAUDE.md — margin boxes render since Chrome 131); audit
report M3 withdrawn accordingly.

~65 new pinning tests; every finding reproduced RED against the real test
DB before its fix. Suite: 58 files / 634 tests green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/__tests__/invoice-pdf-cnb-degrade.test.ts

@@ -0,0 +1,108 @@
+import { describe, it, expect, vi, beforeAll, afterAll } from "vitest";
+import Fastify from "fastify";
+import jwt from "jsonwebtoken";
+import prisma from "../config/database";
+import { config } from "../config/env";
+import invoicesPdfRoutes from "../routes/admin/invoices-pdf";
+import { createInvoice } from "../services/invoices.service";
+import { getRate } from "../services/exchange-rates";
+
+/**
+ * Pinning tests for audit finding M5: a foreign-currency invoice PDF must
+ * degrade gracefully when the CNB rate lookup fails — render WITHOUT the CZK
+ * VAT recap/conversion footnote instead of 500ing the whole preview AND the
+ * NAS archival. The rate only feeds the recap conversion; the document itself
+ * is renderable without it.
+ */
+
+vi.mock("../services/exchange-rates", async (importOriginal) => {
+  const actual =
+    await importOriginal<typeof import("../services/exchange-rates")>();
+  return { ...actual, getRate: vi.fn() };
+});
+
+let app: ReturnType<typeof Fastify>;
+let adminToken: string;
+const createdInvoiceIds: number[] = [];
+
+beforeAll(async () => {
+  app = Fastify({ logger: false });
+  await app.register(invoicesPdfRoutes, { prefix: "/api/admin/invoices-pdf" });
+
+  const admin = await prisma.users.findFirst({
+    where: { roles: { name: "admin" } },
+  });
+  if (!admin) throw new Error("Test setup: admin user not found");
+  adminToken = jwt.sign(
+    { sub: admin.id, username: admin.username, role: "admin" },
+    config.jwt.secret,
+    { expiresIn: "15m" },
+  );
+});
+
+afterAll(async () => {
+  for (const id of createdInvoiceIds)
+    await prisma.invoices.deleteMany({ where: { id } });
+  if (app) await app.close();
+  await prisma.$disconnect();
+});
+
+async function makeEurInvoice() {
+  // Draft → no number consumed; EUR → triggers the CNB rate lookup.
+  const invoice = await createInvoice({
+    status: "draft",
+    currency: "EUR",
+    apply_vat: true,
+    vat_rate: 21,
+    items: [
+      {
+        description: "CNB-DEGRADE-MARKER",
+        quantity: 1,
+        unit_price: 100,
+        vat_rate: 21,
+      },
+    ],
+  });
+  createdInvoiceIds.push(invoice.id);
+  return invoice;
+}
+
+describe("invoice PDF vs unreachable CNB (audit M5)", () => {
+  it("renders the invoice without the CZK recap when the rate lookup throws", async () => {
+    vi.mocked(getRate).mockRejectedValue(
+      new Error("Nepodařilo se získat aktuální kurzy z ČNB"),
+    );
+    const invoice = await makeEurInvoice();
+
+    const res = await app.inject({
+      method: "GET",
+      url: `/api/admin/invoices-pdf/${invoice.id}`,
+      headers: { Authorization: `Bearer ${adminToken}` },
+    });
+
+    expect(res.statusCode).toBe(200);
+    const html = res.body;
+    expect(html).toContain("CNB-DEGRADE-MARKER");
+    // The CZK recap and the conversion footnote are omitted — their numbers
+    // cannot be computed without the rate.
+    expect(html).not.toContain("Rekapitulace DPH v Kč");
+    expect(html).not.toContain("Přepočet kurzem ČNB");
+  });
+
+  it("still renders the recap + conversion footnote when the rate is available", async () => {
+    vi.mocked(getRate).mockResolvedValue(25.0);
+    const invoice = await makeEurInvoice();
+
+    const res = await app.inject({
+      method: "GET",
+      url: `/api/admin/invoices-pdf/${invoice.id}`,
+      headers: { Authorization: `Bearer ${adminToken}` },
+    });
+
+    expect(res.statusCode).toBe(200);
+    const html = res.body;
+    expect(html).toContain("Rekapitulace DPH v Kč");
+    expect(html).toContain("Přepočet kurzem ČNB");
+    expect(html).toContain("25,000");
+  });
+});