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/admin/pages/Settings.tsx

@@ -334,7 +334,7 @@ export default function Settings() {
   }, [sysSettingsData, sysFormInitialized]);
 
   const saveSystemSettingsMutation = useApiMutation<
-    typeof sysForm,
+    Partial<typeof sysForm>,
     { message?: string; error?: string }
   >({
     url: () => `${API_BASE}/company-settings`,
@@ -424,7 +424,24 @@ export default function Settings() {
 
   const handleSaveSystemSettings = async () => {
     try {
-      await saveSystemSettingsMutation.mutateAsync(sysForm);
+      // Send ONLY the fields this tab edits. sysForm also carries
+      // numbering/currency fields captured once at init (sysFormInitialized
+      // never resets), and the backend applies every defined field — sending
+      // the whole form would silently revert a Firma-tab numbering edit made
+      // in the meantime with stale values.
+      await saveSystemSettingsMutation.mutateAsync({
+        break_threshold_hours: sysForm.break_threshold_hours,
+        break_duration_short: sysForm.break_duration_short,
+        break_duration_long: sysForm.break_duration_long,
+        clock_rounding_minutes: sysForm.clock_rounding_minutes,
+        invoice_alert_email: sysForm.invoice_alert_email,
+        leave_notify_email: sysForm.leave_notify_email,
+        smtp_from: sysForm.smtp_from,
+        smtp_from_name: sysForm.smtp_from_name,
+        max_login_attempts: sysForm.max_login_attempts,
+        lockout_minutes: sysForm.lockout_minutes,
+        max_requests_per_minute: sysForm.max_requests_per_minute,
+      });
     } catch (e) {
       alert.error(e instanceof Error ? e.message : "Chyba připojení");
     }