feat(ios): upgrade button in setting (#13645)

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

## Summary by CodeRabbit

- New Features
- Added a Subscription section in Mobile Settings (for signed-in users)
with plan info and an Upgrade button that opens the native paywall.
  - Supports showing “Pro” and “AI” paywalls.
  - Integrated native paywall provider on iOS.

- Style
- Introduced new styling for the subscription card, content, and button.

- Localization
- Added English strings for subscription title, description, and button.

- Chores
- Minor iOS project cleanup and internal wiring to enable the paywall
module.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/frontend/core/src/modules/index.ts

@@ -44,6 +44,7 @@ import { configureNavigationPanelModule } from './navigation-panel';
 import { configureNotificationModule } from './notification';
 import { configureOpenInApp } from './open-in-app';
 import { configureOrganizeModule } from './organize';
+import { configurePaywallModule } from './paywall';
 import { configurePDFModule } from './pdf';
 import { configurePeekViewModule } from './peek-view';
 import { configurePermissionsModule } from './permissions';
@@ -130,4 +131,5 @@ export function configureCommonModules(framework: Framework) {
   configureIndexerEmbeddingModule(framework);
   configureCommentModule(framework);
   configureDocSummaryModule(framework);
+  configurePaywallModule(framework);
 }