Add WebSocket polyfill for Node.js tests

Co-authored-by: miccy <9729864+miccy@users.noreply.github.com>

Author: Copilot

packages/nodejs/test/setup.ts

@@ -0,0 +1,8 @@
+// Polyfill WebSocket for Node.js tests
+// The @evolu/common package accesses globalThis.WebSocket at import time
+import { WebSocket } from "ws";
+
+if (!globalThis.WebSocket) {
+  // @ts-expect-error - ws WebSocket is compatible enough for our needs
+  globalThis.WebSocket = WebSocket;
+}

packages/nodejs/vitest.config.ts

@@ -2,6 +2,7 @@ import { defineConfig } from "vitest/config";
 
 export default defineConfig({
   test: {
+    setupFiles: ["./test/setup.ts"],
     exclude: ["**/node_modules/**", "**/dist/**"],
     include: ["test/**/*.test.ts"],
     coverage: {