fix: resolve TypeScript errors in desktop wallet

- Remove unused MULTIPLIER variable in Send.tsx
- Remove unused Check import in Settings.tsx
- Add vite-env.d.ts for ImportMeta.env types

apps/desktop-wallet/src/pages/Send.tsx

@@ -14,7 +14,6 @@ import { useWalletStore } from '../store/wallet';
  */
 function parseSynToSompi(amountStr: string): bigint | null {
   const DECIMALS = 8;
-  const MULTIPLIER = BigInt(10 ** DECIMALS);
 
   // Clean the input
   const cleaned = amountStr.trim();

apps/desktop-wallet/src/pages/Settings.tsx

@@ -5,7 +5,6 @@ import {
   Shield,
   Key,
   AlertTriangle,
-  Check,
   RefreshCw,
   Download,
 } from 'lucide-react';

apps/desktop-wallet/src/vite-env.d.ts

@@ -0,0 +1,11 @@
+/// <reference types="vite/client" />
+
+interface ImportMetaEnv {
+  readonly PROD: boolean;
+  readonly DEV: boolean;
+  readonly MODE: string;
+}
+
+interface ImportMeta {
+  readonly env: ImportMetaEnv;
+}