fix(ui): preview mode show the pr number

Author: btea

app/components/AppHeader.vue

@@ -218,6 +218,16 @@ onKeyStroke(
       >
         <AppMark class="w-6 h-auto" />
       </NuxtLink>
+      <NuxtLink
+        v-if="!isSearchExpanded && !isOnHomePage && prNumber"
+        :to="`https://github.com/npmx-dev/npmx.dev/pull/${prNumber}`"
+        :aria-label="`Open GitHub pull request ${prNumber}`"
+        class="sm:hidden"
+      >
+        <span class="text-xs px-1.5 py-0.5 rounded badge-green font-sans font-medium ms-2">
+          PR #{{ prNumber }}
+        </span>
+      </NuxtLink>
 
       <!-- Desktop: Logo (navigates home) -->
       <div v-if="showLogo" class="hidden sm:flex flex-shrink-0 items-center">