security: fix all Critical and High findings from FLAWS_REPORT audit

- Auth: pessimistic locking on login tokens and refresh token rotation,
  backup code attempt counter, rate limiting verification
- Schema: unique constraints on business numbers, FK relations,
  unsigned/signed alignment, attendance duplicate prevention
- Invoices/PDFs: DOMPurify sanitization, bounded queries in stats
  and alerts, VAT rounding, Puppeteer error handling
- Orders/Offers: transactional parent+child creation, Zod NaN
  refinement, status enums, uniqueness checks
- Projects/Files: path traversal protection, streamed uploads,
  permission guards, query param validation
- Attendance/HR: duplicate checks, ownership validation, GPS
  restrictions, trip distance validation
- Frontend: modal lock reference counting, XSS escaping in print
  HTML, ref mutation fixes, accessibility attributes

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/services/invoice-alerts.ts

@@ -48,11 +48,15 @@ export async function checkInvoiceAlerts(): Promise<void> {
   const createdInvoices = await prisma.invoices.findMany({
     where: {
       status: { in: ["issued", "overdue"] },
-      due_date: { not: null },
+      due_date: { gte: today, lte: in3days },
     },
-    include: {
+    select: {
+      id: true,
+      invoice_number: true,
+      due_date: true,
+      currency: true,
       customers: { select: { name: true } },
-      invoice_items: true,
+      invoice_items: { select: { quantity: true, unit_price: true } },
     },
   });
 
@@ -105,7 +109,15 @@ export async function checkInvoiceAlerts(): Promise<void> {
   const receivedInvoices = await prisma.received_invoices.findMany({
     where: {
       status: "unpaid",
-      due_date: { not: null },
+      due_date: { gte: today, lte: in3days },
+    },
+    select: {
+      id: true,
+      invoice_number: true,
+      supplier_name: true,
+      amount: true,
+      currency: true,
+      due_date: true,
     },
   });