feat: add Stripe pricing table integration for subscription dialog (conditional on feature flag) (#7288)

Integrates Stripe's pricing table web component into the subscription
dialog when the subscription_tiers_enabled feature flag is active. The
implementation includes a new StripePricingTable component that loads
Stripe's pricing table script and renders the table with proper error
handling and loading states. The subscription dialog now displays the
Stripe pricing table with contact us and enterprise links, using a
1100px width that balances multi-column layout with visual design.
Configuration supports environment variables, remote config, and window
config for the Stripe publishable key and pricing table ID.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7288-feat-add-Stripe-pricing-table-integration-for-subscription-dialog-conditional-on-featur-2c46d73d365081fa9d93c213df118996)
by [Unito](https://www.unito.io)

src/platform/cloud/subscription/components/SubscribeButton.vue

@@ -24,8 +24,9 @@
 
 <script setup lang="ts">
 import Button from 'primevue/button'
-import { computed, onBeforeUnmount, ref } from 'vue'
+import { computed, onBeforeUnmount, ref, watch } from 'vue'
 
+import { useFeatureFlags } from '@/composables/useFeatureFlags'
 import { useSubscription } from '@/platform/cloud/subscription/composables/useSubscription'
 import { isCloud } from '@/platform/distribution/types'
 import { useTelemetry } from '@/platform/telemetry'
@@ -51,12 +52,18 @@ const emit = defineEmits<{
   subscribed: []
 }>()
 
-const { subscribe, isActiveSubscription, fetchStatus } = useSubscription()
+const { subscribe, isActiveSubscription, fetchStatus, showSubscriptionDialog } =
+  useSubscription()
+const { flags } = useFeatureFlags()
+const shouldUseStripePricing = computed(
+  () => isCloud && Boolean(flags.subscriptionTiersEnabled)
+)
 const telemetry = useTelemetry()
 
 const isLoading = ref(false)
 const isPolling = ref(false)
 let pollInterval: number | null = null
+const isAwaitingStripeSubscription = ref(false)
 
 const POLL_INTERVAL_MS = 3000 // Poll every 3 seconds
 const MAX_POLL_DURATION_MS = 5 * 60 * 1000 // Stop polling after 5 minutes
@@ -102,11 +109,27 @@ const stopPolling = () => {
   isLoading.value = false
 }
 
+watch(
+  [isAwaitingStripeSubscription, isActiveSubscription],
+  ([awaiting, isActive]) => {
+    if (shouldUseStripePricing.value && awaiting && isActive) {
+      emit('subscribed')
+      isAwaitingStripeSubscription.value = false
+    }
+  }
+)
+
 const handleSubscribe = async () => {
   if (isCloud) {
     useTelemetry()?.trackSubscription('subscribe_clicked')
   }
 
+  if (shouldUseStripePricing.value) {
+    isAwaitingStripeSubscription.value = true
+    showSubscriptionDialog()
+    return
+  }
+
   isLoading.value = true
   try {
     await subscribe()
@@ -120,5 +143,6 @@ const handleSubscribe = async () => {
 
 onBeforeUnmount(() => {
   stopPolling()
+  isAwaitingStripeSubscription.value = false
 })
 </script>