feat(notifications): add multi-channel notification module with Email, FCM, templates, and event listeners

- Domain: NotificationLog/NotificationPreference entities, repositories, channel value object
- Infrastructure: EmailService (nodemailer/SMTP), FcmService (firebase-admin), TemplateService (Handlebars)
- Application: SendNotification CQRS command, UserRegistered + AgentVerified event listeners
- Presentation: NotificationsController with history, preferences, and templates endpoints
- Prisma: NotificationLog and NotificationPreference models with proper indexes
- Templates: Vietnamese notification templates for user.registered, agent.verified, listing.approved, inquiry.received, password.reset

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/web/components/ui/label.tsx

@@ -0,0 +1,20 @@
+'use client';
+
+import * as React from 'react';
+import { cva, type VariantProps } from 'class-variance-authority';
+import { cn } from '@/lib/utils';
+
+const labelVariants = cva(
+  'text-sm font-medium leading-none peer-disabled:cursor-not-allowed peer-disabled:opacity-70',
+);
+
+export interface LabelProps
+  extends React.LabelHTMLAttributes<HTMLLabelElement>,
+    VariantProps<typeof labelVariants> {}
+
+const Label = React.forwardRef<HTMLLabelElement, LabelProps>(({ className, ...props }, ref) => {
+  return <label ref={ref} className={cn(labelVariants(), className)} {...props} />;
+});
+Label.displayName = 'Label';
+
+export { Label };