feat(listings-frontend): add create/edit form, detail page, and listing components

- Multi-step wizard for listing creation (basic info, location, details, pricing, images)
- Listing detail page with image gallery, property specs, seller/agent info, stats
- Listings index page with filters (transaction type, property type) and pagination
- Edit page with tab-based form (read-only until backend PATCH endpoint available)
- Drag & drop image upload component with preview and multi-file support
- Dashboard layout with navigation bar
- New UI primitives: textarea, select, badge, tabs
- Listings API client with typed endpoints matching backend contract
- Zod validation schemas for all form steps
- Status badges with Vietnamese labels for all listing states
- Responsive design across all pages

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

apps/web/components/ui/badge.tsx

@@ -0,0 +1,33 @@
+import * as React from 'react';
+import { cva, type VariantProps } from 'class-variance-authority';
+import { cn } from '@/lib/utils';
+
+const badgeVariants = cva(
+  'inline-flex items-center rounded-full border px-2.5 py-0.5 text-xs font-semibold transition-colors focus:outline-none focus:ring-2 focus:ring-ring focus:ring-offset-2',
+  {
+    variants: {
+      variant: {
+        default: 'border-transparent bg-primary text-primary-foreground',
+        secondary: 'border-transparent bg-secondary text-secondary-foreground',
+        destructive: 'border-transparent bg-destructive text-destructive-foreground',
+        outline: 'text-foreground',
+        success: 'border-transparent bg-green-100 text-green-800',
+        warning: 'border-transparent bg-yellow-100 text-yellow-800',
+        info: 'border-transparent bg-blue-100 text-blue-800',
+      },
+    },
+    defaultVariants: {
+      variant: 'default',
+    },
+  },
+);
+
+export interface BadgeProps
+  extends React.HTMLAttributes<HTMLDivElement>,
+    VariantProps<typeof badgeVariants> {}
+
+function Badge({ className, variant, ...props }: BadgeProps) {
+  return <div className={cn(badgeVariants({ variant }), className)} {...props} />;
+}
+
+export { Badge, badgeVariants };