feat: NAS storage for invoices/offers, code cleanup, date/time fixes

- NAS storage for created invoices (PDF via puppeteer), received invoices,
  and offers with auto-save on create/edit
- Deterministic file paths derived from DB fields (no file_path column needed)
- Separate NAS mount points: NAS_FINANCIALS_PATH, NAS_OFFERS_PATH
- Invoice language field (cs/en) stored per invoice, replaces lang modal
- Invoices list filtered by month/year matching KPI card selection
- Centralized date helpers (src/utils/date.ts) replacing all .toISOString()
  calls that returned UTC instead of local time
- Attendance project switching uses exact time (not rounded)
- Comment cleanup: removed ~100 unnecessary/Czech comments
- Removed as-any casts in orders and attendance
- Prisma migrations: add invoice language, drop received_invoices BLOB columns

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/routes/admin/received-invoices.ts

@@ -11,6 +11,7 @@ import {
   CreateReceivedInvoiceSchema,
   UpdateReceivedInvoiceSchema,
 } from "../../schemas/received-invoices.schema";
+import { nasFinancialsManager } from "../../services/nas-financials-manager";
 
 const VALID_STATUSES = ["unpaid", "paid"] as const;
 const ALLOWED_SORT_FIELDS = [
@@ -160,16 +161,31 @@ export default async function receivedInvoicesRoutes(
       if (id === null) return;
       const invoice = await prisma.received_invoices.findUnique({
         where: { id },
-        select: { file_data: true, file_name: true, file_mime: true },
+        select: {
+          file_name: true,
+          file_mime: true,
+          year: true,
+          month: true,
+        },
       });
-      if (!invoice?.file_data) return error(reply, "Soubor nenalezen", 404);
+      if (!invoice?.file_name) return error(reply, "Soubor nenalezen", 404);
+
+      const relPath = nasFinancialsManager.buildReceivedPath(
+        invoice.file_name,
+        invoice.year,
+        invoice.month,
+      );
+      const nasFile = nasFinancialsManager.readReceivedInvoice(relPath);
+      if (!nasFile) return error(reply, "Soubor na NAS nenalezen", 404);
 
       const mime = invoice.file_mime || "application/pdf";
-      const filename = invoice.file_name || `received-invoice-${id}.pdf`;
       return reply
         .type(mime)
-        .header("Content-Disposition", `inline; filename="${filename}"`)
-        .send(Buffer.from(invoice.file_data));
+        .header(
+          "Content-Disposition",
+          `inline; filename="${invoice.file_name}"`,
+        )
+        .send(nasFile.data);
     },
   );
 
@@ -183,9 +199,10 @@ export default async function receivedInvoicesRoutes(
         where: { id },
       });
       if (!invoice) return error(reply, "Přijatá faktura nenalezena", 404);
-      // Don't send file_data in detail response (can be large)
-      const { file_data: _fileData, ...rest } = invoice;
-      return success(reply, rest);
+      return success(reply, {
+        ...invoice,
+        has_file: !!invoice.file_name,
+      });
     },
   );
 
@@ -230,6 +247,8 @@ export default async function receivedInvoicesRoutes(
         const now = new Date();
         const createdIds: number[] = [];
 
+        const useNas = nasFinancialsManager.isConfigured();
+
         for (let i = 0; i < files.length; i++) {
           const file = files[i];
           const meta = invoicesMeta[i] || {};
@@ -241,10 +260,34 @@ export default async function receivedInvoicesRoutes(
               ? Math.round((amount - amount / (1 + vatRate / 100)) * 100) / 100
               : 0;
 
+          const issueDate = meta.issue_date
+            ? new Date(String(meta.issue_date))
+            : null;
+          const invoiceMonth = issueDate
+            ? issueDate.getMonth() + 1
+            : Number(meta.month) || now.getMonth() + 1;
+          const invoiceYear = issueDate
+            ? issueDate.getFullYear()
+            : Number(meta.year) || now.getFullYear();
+
+          if (!useNas) {
+            return error(reply, "NAS úložiště není nakonfigurováno", 503);
+          }
+
+          const nasResult = nasFinancialsManager.saveReceivedInvoice(
+            file.name,
+            invoiceYear,
+            invoiceMonth,
+            file.data,
+          );
+          if ("error" in nasResult) {
+            return error(reply, nasResult.error, 503);
+          }
+
           const invoice = await prisma.received_invoices.create({
             data: {
-              month: Number(meta.month) || now.getMonth() + 1,
-              year: Number(meta.year) || now.getFullYear(),
+              month: invoiceMonth,
+              year: invoiceYear,
               supplier_name: meta.supplier_name
                 ? String(meta.supplier_name)
                 : file.name,
@@ -263,7 +306,6 @@ export default async function receivedInvoicesRoutes(
               status: "unpaid",
               notes: meta.notes ? String(meta.notes) : null,
               uploaded_by: request.authData?.userId,
-              file_data: Uint8Array.from(file.data),
               file_name: file.name,
               file_mime: file.mime,
               file_size: file.size,
@@ -488,6 +530,15 @@ export default async function receivedInvoicesRoutes(
       });
       if (!existing) return error(reply, "Přijatá faktura nenalezena", 404);
 
+      if (existing.file_name) {
+        const relPath = nasFinancialsManager.buildReceivedPath(
+          existing.file_name,
+          existing.year,
+          existing.month,
+        );
+        nasFinancialsManager.deleteReceivedInvoice(relPath);
+      }
+
       await prisma.received_invoices.delete({ where: { id } });
       await logAudit({
         request,