fix: move webidl-conversions polyfill to config file top

Apply ArrayBuffer/SharedArrayBuffer polyfills at the very top of the
vite.config.test.ts file, before any imports. This ensures the polyfills
are applied before webidl-conversions is loaded by any dependencies.

The previous globalSetup approach didn't work in CI because globalSetup
runs in a separate context after modules are already loaded. Moving the
polyfill to the config file ensures it runs early enough to prevent
'Cannot read properties of undefined (reading get)' errors in Node 18.

Author: chiptus

vite.config.test.ts

@@ -1,3 +1,29 @@
+// Polyfill ArrayBuffer and SharedArrayBuffer properties before any imports
+// This prevents webidl-conversions errors in Node 18 CI environment
+if (
+  typeof ArrayBuffer !== "undefined" &&
+  !Object.getOwnPropertyDescriptor(ArrayBuffer.prototype, "resizable")
+) {
+  Object.defineProperty(ArrayBuffer.prototype, "resizable", {
+    get() {
+      return false;
+    },
+    configurable: true,
+  });
+}
+
+if (
+  typeof SharedArrayBuffer !== "undefined" &&
+  !Object.getOwnPropertyDescriptor(SharedArrayBuffer.prototype, "growable")
+) {
+  Object.defineProperty(SharedArrayBuffer.prototype, "growable", {
+    get() {
+      return false;
+    },
+    configurable: true,
+  });
+}
+
 import { defineConfig } from "vitest/config";
 import react from "@vitejs/plugin-react-swc";
 import path from "path";