feat(ios): hashcash in swift (#8602)

packages/frontend/apps/ios/src/plugins/hashcash/definitions.ts

@@ -0,0 +1,6 @@
+export interface HashcashPlugin {
+  hash(options: {
+    challenge: string;
+    bits?: number;
+  }): Promise<{ value: string }>;
+}

packages/frontend/apps/ios/src/plugins/hashcash/index.ts

@@ -0,0 +1,8 @@
+import { registerPlugin } from '@capacitor/core';
+
+import type { HashcashPlugin } from './definitions';
+
+const Hashcash = registerPlugin<HashcashPlugin>('Hashcash');
+
+export * from './definitions';
+export { Hashcash };