feat: username/password authentication for admin and merchant panels

- Add PasswordHasher utility (PBKDF2/SHA-256, 100k iterations)
- Add Username + PasswordHash fields to Employee and SystemAdmin entities
- EF migration: AddPasswordLogin (nullable columns on both tables)
- Meezi.API: POST /api/auth/login (employee password login, CHOOSE_CAFE support)
- Meezi.API: PUT/DELETE /api/cafes/{id}/employees/{id}/credentials (Owner/Manager only)
- Meezi.Admin.API: POST /api/admin/auth/login + PUT /api/admin/auth/password
- Dashboard login page: OTP / Password tabs
- Admin login page: OTP / Password tabs
- HR screen: new Credentials tab for setting employee username/password
- PlatformDataSeeder: ensure system admin + integration settings in production
- Trial countdown banner: updated deadline to 1 Tir 1405 (Jun 22)
- i18n: fa/en/ar updated for all new UI strings

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

web/dashboard/src/components/layout/trial-countdown-banner.tsx

@@ -5,8 +5,8 @@ import { useLocale } from "next-intl";
 import { useRouter } from "@/i18n/routing";
 import { Clock, X, Zap } from "lucide-react";
 
-// 14 Khordad 1405 = June 4, 2026  (Tehran UTC+3:30)
-const DEADLINE = new Date("2026-06-04T00:00:00+03:30");
+// 1 Tir 1405 = June 22, 2026  (Tehran IRDT UTC+4:30)
+const DEADLINE = new Date("2026-06-22T00:00:00+04:30");
 const STORAGE_KEY = "meezi_trial_banner_v1";
 
 interface TimeLeft {
@@ -78,11 +78,11 @@ export function TrialCountdownBanner() {
 
   const textFa = expired
     ? "دوره آزمایشی میزی به پایان رسید. برای ادامه پلن انتخاب کنید."
-    : "دوره آزمایشی رایگان تا ۱۴ خرداد ۱۴۰۵";
+    : "دوره آزمایشی رایگان تا ۱ تیر ۱۴۰۵";
 
   const textEn = expired
     ? "Your Meezi trial has ended. Choose a plan to continue."
-    : "Free trial ends 14 Khordad 1405 (Jun 4)";
+    : "Free trial ends 1 Tir 1405 (Jun 22)";
 
   const Digit = ({ value, label }: { value: number; label: string }) => (
     <div className="flex flex-col items-center">