feat: handling subscription tier button link parameter (#7553)

## Summary

Discussion here:
https://comfy-organization.slack.com/archives/C0A0XANFJRE/p1764899027465379

Implement: Subscription tier query parameter for direct checkout flow

Example button link: `/cloud/subscribe?tier=standard`

`tier` could be `standard`, `creator` or `pro`
`cycle` could be `monthly` or `yearly`. it is optional, and `monthly` by
default.

<!-- One sentence describing what changed and why. -->

## Changes

- **What**: <!-- Core functionality added/modified -->
- Add a landing page called `CloudSubscriptionRedirectView.vue` to
handling the subscription tier button link parameter
  - Extract subscription handling logic from `PriceTable.vue`
 
- **Breaking**: <!-- Any breaking changes (if none, remove this line)
-->
  - Code change touched  `PriceTable.vue`
- **Dependencies**: <!-- New dependencies (if none, remove this line)
-->

## Review Focus
- link will redirect to login url, when cloud app not login
- after login, the cloud app will redirect to CloudSubscriptionRedirect
page
- wait for several seconds, the cloud app will be redirected to checkout
page

<!-- Critical design decisions or edge cases that need attention -->

<!-- If this PR fixes an issue, uncomment and update the line below -->
<!-- Fixes #ISSUE_NUMBER -->

## Screenshots (if applicable)

![Kapture 2025-12-16 at 18 43
28](https://github.com/user-attachments/assets/affbc18f-d45c-4953-b06a-fc797eba6804)


<!-- Add screenshots or video recording to help explain your changes -->

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7553-feat-handling-subscription-tier-button-link-parameter-2cb6d73d365081ee9580e89090248300)
by [Unito](https://www.unito.io)

---------

Co-authored-by: GitHub Action <action@github.com>

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

@@ -252,7 +252,6 @@ import { useI18n } from 'vue-i18n'
 import Button from '@/components/ui/button/Button.vue'
 import { useFirebaseAuthActions } from '@/composables/auth/useFirebaseAuthActions'
 import { useErrorHandling } from '@/composables/useErrorHandling'
-import { getComfyApiBaseUrl } from '@/config/comfyApi'
 import { t } from '@/i18n'
 import { useSubscription } from '@/platform/cloud/subscription/composables/useSubscription'
 import {
@@ -263,13 +262,10 @@ import type {
   TierKey,
   TierPricing
 } from '@/platform/cloud/subscription/constants/tierPricing'
+import { performSubscriptionCheckout } from '@/platform/cloud/subscription/utils/subscriptionCheckoutUtil'
 import { isPlanDowngrade } from '@/platform/cloud/subscription/utils/subscriptionTierRank'
 import type { BillingCycle } from '@/platform/cloud/subscription/utils/subscriptionTierRank'
 import { isCloud } from '@/platform/distribution/types'
-import {
-  FirebaseAuthStoreError,
-  useFirebaseAuthStore
-} from '@/stores/firebaseAuthStore'
 import type { components } from '@/types/comfyRegistryTypes'
 
 type SubscriptionTier = components['schemas']['SubscriptionTier']
@@ -332,7 +328,6 @@ const tiers: PricingTierConfig[] = [
 ]
 
 const { n } = useI18n()
-const { getAuthHeader } = useFirebaseAuthStore()
 const { isActiveSubscription, subscriptionTier, isYearlySubscription } =
   useSubscription()
 const { accessBillingPortal, reportError } = useFirebaseAuthActions()
@@ -384,12 +379,13 @@ const getButtonLabel = (tier: PricingTierConfig): string => {
     : t('subscription.subscribeTo', { plan: planName })
 }
 
-const getButtonSeverity = (tier: PricingTierConfig): 'primary' | 'secondary' =>
-  isCurrentPlan(tier.key)
-    ? 'secondary'
-    : tier.key === 'creator'
-      ? 'primary'
-      : 'secondary'
+const getButtonSeverity = (
+  tier: PricingTierConfig
+): 'primary' | 'secondary' => {
+  if (isCurrentPlan(tier.key)) return 'secondary'
+  if (tier.key === 'creator') return 'primary'
+  return 'secondary'
+}
 
 const getButtonTextClass = (tier: PricingTierConfig): string =>
   tier.key === 'creator'
@@ -405,47 +401,6 @@ const getAnnualTotal = (tier: PricingTierConfig): number =>
 const getCreditsDisplay = (tier: PricingTierConfig): number =>
   tier.pricing.credits * (currentBillingCycle.value === 'yearly' ? 12 : 1)
 
-const initiateCheckout = async (tierKey: CheckoutTierKey) => {
-  const authHeader = await getAuthHeader()
-  if (!authHeader) {
-    throw new FirebaseAuthStoreError(t('toastMessages.userNotAuthenticated'))
-  }
-
-  const checkoutTier = getCheckoutTier(tierKey, currentBillingCycle.value)
-  const response = await fetch(
-    `${getComfyApiBaseUrl()}/customers/cloud-subscription-checkout/${checkoutTier}`,
-    {
-      method: 'POST',
-      headers: { ...authHeader, 'Content-Type': 'application/json' }
-    }
-  )
-
-  if (!response.ok) {
-    let errorMessage = 'Failed to initiate checkout'
-    try {
-      const errorData = await response.json()
-      errorMessage = errorData.message || errorMessage
-    } catch {
-      // If JSON parsing fails, try to get text response or use HTTP status
-      try {
-        const errorText = await response.text()
-        errorMessage =
-          errorText || `HTTP ${response.status} ${response.statusText}`
-      } catch {
-        errorMessage = `HTTP ${response.status} ${response.statusText}`
-      }
-    }
-
-    throw new FirebaseAuthStoreError(
-      t('toastMessages.failedToInitiateSubscription', {
-        error: errorMessage
-      })
-    )
-  }
-
-  return await response.json()
-}
-
 const handleSubscribe = wrapWithErrorHandlingAsync(
   async (tierKey: CheckoutTierKey) => {
     if (!isCloud || isLoading.value || isCurrentPlan(tierKey)) return
@@ -475,10 +430,7 @@ const handleSubscribe = wrapWithErrorHandlingAsync(
           await accessBillingPortal(checkoutTier)
         }
       } else {
-        const response = await initiateCheckout(tierKey)
-        if (response.checkout_url) {
-          window.open(response.checkout_url, '_blank')
-        }
+        await performSubscriptionCheckout(tierKey, currentBillingCycle.value)
       }
     } finally {
       isLoading.value = false