feat(wallets): add isDefault field to wallet model and implement setDefaultWallet functionality

apps/backend/src/modules/wallets/handlers/setDefaultWallet.ts

@@ -0,0 +1,8 @@
+import type { Context } from "hono";
+import { setDefaultWallet } from "../wallets.service";
+
+export async function setDefaultWalletHandler(c: Context) {
+  const id = Number(c.req.param("id"));
+  const result = await setDefaultWallet(id);
+  return c.json(result);
+}