Show staging tag for staging firebase (#3693)

src/components/dialog/header/SettingDialogHeader.vue

@@ -3,9 +3,21 @@
     <h2 class="px-4">
       <i class="pi pi-cog" />
       <span>{{ $t('g.settings') }}</span>
+      <Tag
+        v-if="isStaging"
+        value="staging"
+        severity="warn"
+        class="ml-2 text-xs"
+      />
     </h2>
   </div>
 </template>
+<script setup lang="ts">
+import Tag from 'primevue/tag'
+
+// @ts-expect-error: Global variable from vite build defined in global.d.ts
+const isStaging = !window.__USE_PROD_CONFIG__
+</script>
 
 <style scoped>
 .pi-cog {