fix(web): handle null maxListings/maxSavedSearches on ENTERPRISE plan

Seed stores null (not -1) for unlimited quotas on the ENTERPRISE tier.
PlanDto now types these as `number | null`. PricingPage treats null the
same as -1 — both render 'Không giới hạn' instead of 'null tin đăng'.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/web/app/[locale]/(public)/pricing/page.tsx

@@ -87,10 +87,13 @@ function getFeatureValue(
   key: string,
 ): boolean | number | string {
   if (key === 'maxListings') {
-    return plan.maxListings === -1 ? 'Không giới hạn' : plan.maxListings;
+    // null and -1 both signal "unlimited" (seed uses null, business logic uses -1)
+    return plan.maxListings == null || plan.maxListings === -1
+      ? 'Không giới hạn'
+      : plan.maxListings;
   }
   if (key === 'maxSavedSearches') {
-    return plan.maxSavedSearches === -1
+    return plan.maxSavedSearches == null || plan.maxSavedSearches === -1
       ? 'Không giới hạn'
       : plan.maxSavedSearches;
   }
@@ -300,17 +303,19 @@ export default function PricingPage() {
                       <li className="flex items-center gap-2">
                         <Check className="h-4 w-4 shrink-0 text-green-600" />
                         <span>
-                          {plan.maxListings === -1
+                          {plan.maxListings == null || plan.maxListings === -1
                             ? t('unlimited')
-                            : `${plan.maxListings} ${t('listingsCount')}`}
+                            : `${plan.maxListings}`}{' '}
+                          {t('listingsCount')}
                         </span>
                       </li>
                       <li className="flex items-center gap-2">
                         <Check className="h-4 w-4 shrink-0 text-green-600" />
                         <span>
-                          {plan.maxSavedSearches === -1
+                          {plan.maxSavedSearches == null || plan.maxSavedSearches === -1
                             ? t('unlimited')
-                            : `${plan.maxSavedSearches} ${t('savedSearchesCount')}`}
+                            : `${plan.maxSavedSearches}`}{' '}
+                          {t('savedSearchesCount')}
                         </span>
                       </li>
                       <li className="flex items-center gap-2">

apps/web/lib/subscription-api.ts

@@ -6,8 +6,8 @@ export interface PlanDto {
   name: string;
   priceMonthlyVND: string;
   priceYearlyVND: string;
-  maxListings: number;
-  maxSavedSearches: number;
+  maxListings: number | null;   // null = unlimited (ENTERPRISE tier)
+  maxSavedSearches: number | null;
   features: Record<string, boolean | number | string>;
   isActive: boolean;
 }