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/services/attendance.service.ts

@@ -1,6 +1,7 @@
 import { attendance_leave_type, Prisma } from "@prisma/client";
 import prisma from "../config/database";
 import { getBusinessDaysInMonth } from "../utils/czech-holidays";
+import { localDateStr } from "../utils/date";
 
 type AttendanceWithRelations = Prisma.attendanceGetPayload<{
   include: {
@@ -254,7 +255,6 @@ export async function getStatus(userId: number) {
   };
 
   // 5) Project logs for ongoing shift
-  // Collect all project IDs from completed shifts for name lookup
   const completedProjectIds = new Set<number>();
   for (const shift of todayShiftsRaw) {
     for (const log of shift.attendance_project_logs) {
@@ -262,7 +262,6 @@ export async function getStatus(userId: number) {
     }
   }
 
-  // Fetch project names for completed shifts
   const completedProjectNames = new Map<number, string>();
   if (completedProjectIds.size > 0) {
     const projects = await prisma.projects.findMany({
@@ -277,7 +276,6 @@ export async function getStatus(userId: number) {
     }
   }
 
-  // Enrich today's completed shifts with project names
   const todayShifts = todayShiftsRaw.map((shift) => ({
     ...shift,
     project_logs: shift.attendance_project_logs.map((l) => ({
@@ -337,7 +335,7 @@ export async function getStatus(userId: number) {
     today_shifts: todayShifts,
     leave_balance: leaveBalance,
     monthly_fund: monthlyFund,
-    date: now.toISOString().split("T")[0],
+    date: localDateStr(now),
     project_logs: projectLogs,
     active_project_id: activeProjectId,
   };
@@ -759,7 +757,6 @@ export async function getPrintData(
 
   const fundHours = getBusinessDaysInMonth(yr, mo - 1) * 8;
 
-  // Load project names for enrichment
   const typedRecords = records as AttendanceWithRelations[];
 
   const projectIds = [
@@ -784,7 +781,6 @@ export async function getPrintData(
     }
   }
 
-  // Group records by user and calculate totals
   const userTotals: Record<string, Record<string, unknown>> = {};
   for (const rec of typedRecords) {
     const uid = String(rec.user_id);
@@ -806,7 +802,6 @@ export async function getPrintData(
       };
     }
 
-    // Build record with project_logs for frontend
     const projectLogs =
       rec.attendance_project_logs?.map((log) => ({
         project_id: log.project_id,
@@ -843,7 +838,6 @@ export async function getPrintData(
     }
   }
 
-  // Calculate fund coverage per user
   for (const uid of Object.keys(userTotals)) {
     const ut = userTotals[uid];
     const workedH = Math.round(((ut.minutes as number) / 60) * 10) / 10;
@@ -864,7 +858,6 @@ export async function getPrintData(
     );
   }
 
-  // Leave balances
   const leaveBalances: Record<string, Record<string, number>> = {};
   const balanceRecords = await prisma.leave_balances.findMany({
     where: { year: yr },
@@ -878,7 +871,6 @@ export async function getPrintData(
     };
   }
 
-  // Selected user name
   let selectedUserName = "";
   if (filterUserId) {
     const u = users.find((u) => u.id === filterUserId);
@@ -912,7 +904,8 @@ export async function getActiveProjects() {
   });
   return activeProjects.map((p) => ({
     id: p.id,
-    name: p.project_number ? `${p.project_number} – ${p.name}` : p.name,
+    name: p.name,
+    project_number: p.project_number ?? "",
   }));
 }
 
@@ -1069,9 +1062,7 @@ export async function bulkCreateAttendance(data: BulkAttendanceData) {
     select: { user_id: true, shift_date: true },
   });
   const existingSet = new Set(
-    existing.map(
-      (r) => `${r.user_id}:${r.shift_date.toISOString().split("T")[0]}`,
-    ),
+    existing.map((r) => `${r.user_id}:${localDateStr(r.shift_date)}`),
   );
 
   let inserted = 0;
@@ -1080,7 +1071,7 @@ export async function bulkCreateAttendance(data: BulkAttendanceData) {
   for (const userId of data.user_ids.map(Number)) {
     for (let day = 1; day <= daysInMonth; day++) {
       const date = new Date(yr, mo - 1, day);
-      const dateStr = date.toISOString().split("T")[0];
+      const dateStr = localDateStr(date);
       const dow = date.getDay();
 
       if (dow === 0 || dow === 6) continue;
@@ -1136,7 +1127,7 @@ export async function createLeave(data: LeaveData, authUserId: number) {
   while (current <= end) {
     const dow = current.getDay();
     if (dow !== 0 && dow !== 6) {
-      const dateStr = current.toISOString().split("T")[0];
+      const dateStr = localDateStr(current);
       const shiftDate = new Date(
         Date.UTC(
           current.getFullYear(),
@@ -1161,7 +1152,6 @@ export async function createLeave(data: LeaveData, authUserId: number) {
     current.setDate(current.getDate() + 1);
   }
 
-  // Update leave balance for vacation/sick
   const totalLeaveHours =
     created * (data.leave_hours ? Number(data.leave_hours) : 8);
   if (