subscription page (#6064)

Summary

Implements cloud subscription management UI and flow for ComfyUI Cloud
users.

  Core Features:
- Subscription Status Tracking: Global reactive state management for
subscription status across all components
  using shared subscriptionStatus ref
- Subscribe to Run Button: Replaces the Run button in the actionbar with
a "Subscribe to Run" button for users
  without active subscriptions
- Subscription Required Dialog: Modal dialog with subscription benefits,
pricing, and checkout flow with video
  background
- Subscription Settings Panel: New settings panel showing subscription
status, renewal date, and quick access to
  billing management
- Auto-detection & Polling: Automatically polls subscription status
after checkout completion and syncs state
  across the application


https://github.com/user-attachments/assets/f41b8e6a-5845-48a7-8169-3a6fc0d2e5c8



┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6064-subscription-page-28d6d73d36508135a2a0fe7c94b40852)
by [Unito](https://www.unito.io)

---------

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

src/stores/firebaseAuthStore.ts

@@ -39,7 +39,7 @@ type AccessBillingPortalResponse =
 type AccessBillingPortalReqBody =
   operations['AccessBillingPortal']['requestBody']
 
-class FirebaseAuthStoreError extends Error {
+export class FirebaseAuthStoreError extends Error {
   constructor(message: string) {
     super(message)
     this.name = 'FirebaseAuthStoreError'