fix: restore InMemory storage for Ark wallet initialization

The revert in #3522 was based on a misdiagnosis — the actual cause of
dev API downtime was a FK constraint violation in the sell-if-deficit
migration, not the Ark InMemory imports.

Without explicit storage config, the Ark SDK falls back to IndexedDB
which is not available in Node.js, causing wallet initialization to fail.

Author: TaprootFreak

src/integration/blockchain/ark/__tests__/ark-client.spec.ts

@@ -1,6 +1,16 @@
 import { Wallet } from '@arkade-os/sdk';
 import { ArkClient } from '../ark-client';
 
+// Mock the SDK to provide InMemory repositories
+jest.mock('@arkade-os/sdk', () => {
+  const actualSdk = jest.requireActual('@arkade-os/sdk');
+  return {
+    ...actualSdk,
+    InMemoryWalletRepository: class MockWalletRepository {},
+    InMemoryContractRepository: class MockContractRepository {},
+  };
+});
+
 // Mock config to provide ark credentials
 jest.mock('src/config/config', () => ({
   GetConfig: () => ({

src/integration/blockchain/ark/ark-client.ts

@@ -1,4 +1,4 @@
-import { Wallet, SingleKey } from '@arkade-os/sdk';
+import { Wallet, SingleKey, InMemoryWalletRepository, InMemoryContractRepository } from '@arkade-os/sdk';
 import { Currency } from '@uniswap/sdk-core';
 import { GetConfig } from 'src/config/config';
 import { DfxLogger } from 'src/shared/services/dfx-logger';
@@ -102,6 +102,10 @@ export class ArkClient extends BlockchainClient {
     const wallet = await Wallet.create({
       identity,
       arkServerUrl,
+      storage: {
+        walletRepository: new InMemoryWalletRepository(),
+        contractRepository: new InMemoryContractRepository(),
+      },
     });
 
     return wallet;