migration: integrate openiap-gql 1.0 type system (#209)

## Summary
- unify exported types around the generated schema
- align runtime helpers, hooks, and docs with the new definitions
- applied [OpenIAP GQL
1.0](https://github.com/hyodotdev/openiap-gql/releases/tag/1.0.0)

## Testing
- npm run lint:tsc
- npm test
- npm run build


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **New Features**
  - deepLinkToSubscriptionsAndroid added.
  - useIAP option shouldAutoSyncPurchases introduced.
- Centralized types expose ReceiptValidationResult and VoidResult; new
PurchaseError surface for cross-platform error mapping.

- **Refactor**
- AppTransactionIOS renamed to AppTransaction; error codes standardized
(removed E_ prefix).
  - getAvailablePurchases() is now no-arg.
- finishTransaction now returns VoidResult | boolean; validateReceipt
returns ReceiptValidationResult.
  - Subscription requests moved to platform-scoped props.

- **Documentation**
- Multiple docs and examples reformatted and updated to reflect API and
naming changes.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: hyochan

README.md

@@ -14,20 +14,18 @@
 
 **[📖 Visit our comprehensive documentation site →](https://hyochan.github.io/expo-iap)**
 
-
 ## Notice
 
-The `expo-iap` module has been migrated from [react-native-iap](https://github.com/dooboolab/react-native-iap). While we initially considered fully merging everything into `react-native-iap`, we ultimately decided to maintain the two libraries in parallel, each tailored to its own ecosystem.  
+The `expo-iap` module has been migrated from [react-native-iap](https://github.com/dooboolab/react-native-iap). While we initially considered fully merging everything into `react-native-iap`, we ultimately decided to maintain the two libraries in parallel, each tailored to its own ecosystem.
 
-- **`react-native-iap`** → a **Nitro Modules–based** implementation for React Native.  
-- **`expo-iap`** → an **Expo Module** with tighter integration and smoother compatibility in the Expo ecosystem.  
+- **`react-native-iap`** → a **Nitro Modules–based** implementation for React Native.
+- **`expo-iap`** → an **Expo Module** with tighter integration and smoother compatibility in the Expo ecosystem.
 
-Both libraries will continue to be maintained in parallel going forward.  
+Both libraries will continue to be maintained in parallel going forward.
 
 📖 See the [Future Roadmap and Discussion](https://github.com/dooboolab-community/react-native-iap/discussions/2754) for more details.  
 👉 Stay updated via the [Current Project Status comment](https://github.com/dooboolab-community/react-native-iap/discussions/2754#discussioncomment-10510249).
 
-
 ## Installation
 
 ```bash

docs/CONVENTIONS.md

@@ -190,7 +190,7 @@ Platform-specific types:
 
 - `ProductIOS`, `ProductAndroid`
 - `PurchaseErrorIOS`, `PurchaseErrorAndroid`
-- `AppTransactionIOS`, `SubscriptionOfferAndroid`
+- `AppTransaction`, `SubscriptionOfferAndroid`
 
 Cross-platform types:
 

docs/blog/2025-09-13-v3.0.1.md

@@ -17,4 +17,3 @@ After prebuild
 
 - iOS: Not seeing `pod 'openiap'` in your Podfile is expected; it’s pulled in via the Podspec.
 - Android: Exactly one `openiap-google:1.1.0` line inside `dependencies {}`. In local mode the Maven line is removed and `project(':openiap-google')` is used.
-

docs/docs/api/error-codes.md

@@ -197,9 +197,7 @@ ErrorCodeUtils.getNativeErrorCode(errorCode: ErrorCode): string
 **Example**:
 
 ```tsx
-const nativeCode = ErrorCodeUtils.getNativeErrorCode(
-  ErrorCode.UserCancelled,
-);
+const nativeCode = ErrorCodeUtils.getNativeErrorCode(ErrorCode.UserCancelled);
 console.log(nativeCode); // Platform-specific code
 ```
 
@@ -244,10 +242,7 @@ ErrorCodeUtils.toPlatformCode(
 
 ```tsx
 // iOS
-const iosCode = ErrorCodeUtils.toPlatformCode(
-  ErrorCode.UserCancelled,
-  'ios',
-);
+const iosCode = ErrorCodeUtils.toPlatformCode(ErrorCode.UserCancelled, 'ios');
 console.log(iosCode); // 2
 
 // Android

docs/docs/api/index.md

@@ -7,6 +7,7 @@ import AdFitTopFixed from "@site/src/uis/AdFitTopFixed";
 Welcome to the Expo IAP API documentation. Here you'll find comprehensive guides and references for all the features and functionality available in Expo IAP.
 
 Note: expo-iap follows the OpenIAP API model for consistency across platforms and SDKs. For the canonical API surface, see OpenIAP APIs:
+
 - https://www.openiap.dev/docs/apis
 
 ## Available APIs

docs/docs/api/methods/core-methods.md

@@ -271,7 +271,7 @@ const completePurchase = async (purchase) => {
   - `purchase` (Purchase): The purchase object to finish
   - `isConsumable?` (boolean): Whether the product is consumable (Android)
 
-**Returns:** `Promise<PurchaseResult | boolean>`
+**Returns:** `Promise<VoidResult | boolean>`
 
 ## getAvailablePurchases()
 
@@ -707,10 +707,10 @@ const fetchAppTransaction = async () => {
 };
 ```
 
-**Returns:** `Promise<AppTransactionIOS | null>`
+**Returns:** `Promise<AppTransaction | null>`
 
 ```ts
-interface AppTransactionIOS {
+interface AppTransaction {
   appTransactionId?: string; // iOS 18.4+
   originalPlatform?: string; // iOS 18.4+
   bundleId: string;