[POC][DO_NOT_MERGE] feat: customer billing portal POC

[brobro10000]

This pull request adds functionality to allow users to view their purchase receipt by introducing a "View Receipt" button in the purchase summary. The implementation includes a new hook to create a billing portal session, supporting backend integration and query management. The most important changes are summarized below:

Screen.Recording.2025-10-01.at.1.09.55.AM.mov

UI Enhancements:

• Added a ReceiptButton component to the PurchaseSummary card, providing users with a "View Receipt" button that links to their billing portal session if available. (src/components/PurchaseSummary/PurchaseSummary.tsx, src/components/PurchaseSummary/ReceiptButton.tsx) [1] [2] [3]

Data Layer & API Integration:

• Implemented the useCreateBillingPortalSession hook to handle fetching the billing portal session URL, integrating user context and backend query logic. (src/components/app/data/hooks/useCreateBillingPortalSession.tsx, src/components/app/data/hooks/index.ts) [1] [2]
• Added queryCreateBillingPortalSession to the data queries, enabling requests to the backend for creating billing portal sessions. (src/components/app/data/queries/queries.ts)
• Registered the createBillingPortalSession query key and function in the query key factory for consistent query management. (src/components/app/data/queries/queryKeyFactory.ts) [1] [2]
• Created the create-billing-portal.ts service to handle authenticated API requests for creating billing portal sessions. (src/components/app/data/services/create-billing-portal.ts)

Type Improvements:

• Updated the type signature for determineExistingCheckoutIntentState to ensure correct intent typing. (src/components/app/routes/loaders/utils.ts)

This PR requires the create portal session endpoint to be updated.
openedx/enterprise-access#860

[Copilot]

Pull Request Overview

This PR introduces a customer billing portal proof-of-concept by adding a "View Receipt" button to the purchase summary. The feature is currently stubbed and only enables the button when users have a valid Stripe customer ID.

• Added a new ReceiptButton component with conditional enabling based on Stripe customer ID
• Integrated the receipt button into the PurchaseSummary component's footer
• Updated type definitions to ensure proper checkout intent data handling

Reviewed Changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated no comments.

File	Description
src/components/app/routes/loaders/utils.ts	Updated type signature to require both checkout intent and success properties
src/components/PurchaseSummary/ReceiptButton.tsx	New component implementing the stub receipt button with conditional enabling
src/components/PurchaseSummary/PurchaseSummary.tsx	Added receipt button to the purchase summary card footer

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