refactor(auth): use generated OpenAPI type for customer creation (#14852)

## Summary

Replace the hand-rolled `CreateCustomerPayload` in `authStore` with the
generated OpenAPI `CreateCustomerRequest`, now that the comfy-api spec
declares both `turnstile_token` and `signup_source`.

## Changes

- **What**: `createCustomer` types its request body from
`operations['createCustomer']` (the generated `@comfyorg/registry-types`
contract) instead of a local interface, so the field set drift-checks
against the backend at compile time. `signup_source` is always set from
the client build (`DISTRIBUTION`), so the caller-facing param is
`Omit<CreateCustomerRequest, 'signup_source'>` rather than a shape that
advertises a field callers cannot actually set.
- **Breaking**: none. Runtime behavior is unchanged (body is still `{
...payload, signup_source: DISTRIBUTION }`).

## Review Focus

Follow-up to #14528. The inline schema override is removed now that the
backend regenerated types carry `turnstile_token` + `signup_source`, and
the `payload` param no longer exposes the always-overwritten
`signup_source`.

Verified locally: `vue-tsc --noEmit` clean, `authStore.test.ts` 88/88
pass, eslint clean.

## Screenshots (if applicable)

Author: deepme987

src/stores/authStore.ts

@@ -24,7 +24,6 @@ import { getComfyApiBaseUrl } from '@/config/comfyApi'
 import { t } from '@/i18n'
 import { fetchWithUnifiedRemint } from '@/platform/auth/unified/remintRetry'
 import { DISTRIBUTION, isCloud } from '@/platform/distribution/types'
-import type { Distribution } from '@/platform/distribution/types'
 import {
   clearPreservedQuery,
   getPreservedQueryParam
@@ -46,21 +45,9 @@ type CreditPurchasePayload =
   operations['InitiateCreditPurchase']['requestBody']['content']['application/json']
 type CreateCustomerResponse =
   operations['createCustomer']['responses']['201']['content']['application/json']
-
-/**
- * Request body for createCustomer. The Cloudflare Turnstile token captured at
- * signup is forwarded to the backend as `turnstile_token` (snake_case), which
- * reads this field on the CreateCustomer request; it is omitted for non-signup
- * flows and on OSS / localhost where Turnstile is not rendered.
- *
- * TODO: replace with the generated `operations['createCustomer']` request-body
- * type once the backend OpenAPI spec includes `turnstile_token`, so the field
- * name/optionality drift-checks against the backend at compile time.
- */
-type CreateCustomerPayload = {
-  turnstile_token?: string
-  signup_source?: Distribution
-}
+type CreateCustomerPayload = NonNullable<
+  operations['createCustomer']['requestBody']
+>['content']['application/json']
 type GetCustomerBalanceResponse =
   operations['GetCustomerBalance']['responses']['200']['content']['application/json']
 type AccessBillingPortalResponse =
@@ -392,7 +379,7 @@ export const useAuthStore = defineStore('auth', () => {
   }
 
   const createCustomer = async (
-    payload?: CreateCustomerPayload
+    payload?: Omit<CreateCustomerPayload, 'signup_source'>
   ): Promise<CreateCustomerResponse> => {
     const sessionUserId = currentUser.value?.uid
     const authHeader = await getAuthHeader()
@@ -560,7 +547,7 @@ export const useAuthStore = defineStore('auth', () => {
     action: (auth: Auth) => Promise<T>,
     options: {
       createCustomer?: boolean
-      customerPayload?: CreateCustomerPayload
+      customerPayload?: Omit<CreateCustomerPayload, 'signup_source'>
     } = {}
   ): Promise<T> => {
     loading.value = true