engine moved to a separate node.js module

vite.config.ts

@@ -1,6 +1,29 @@
+import { fileURLToPath } from 'node:url';
+import path from 'node:path';
 import { defineConfig } from 'vite';
 import react from '@vitejs/plugin-react';
 
+const rootDir = path.dirname(fileURLToPath(import.meta.url));
+const engineDir = path.resolve(rootDir, '../engine');
+
 export default defineConfig({
   plugins: [react()],
+  resolve: {
+    // Follow the node_modules symlink to the real sibling directory, so Vite's dev server
+    // watches and transforms the actual engine source files (not a frozen pre-bundled copy).
+    preserveSymlinks: false,
+  },
+  optimizeDeps: {
+    // Treat @incgame/engine as first-party source, not a vendor dependency to pre-bundle once
+    // and cache — otherwise edits to the engine package wouldn't trigger HMR until a full
+    // dev-server restart.
+    exclude: ['@incgame/engine'],
+  },
+  server: {
+    fs: {
+      // The engine package lives outside this project's root (a sibling directory reached
+      // through a node_modules symlink); allow Vite to serve/watch files from there too.
+      allow: [rootDir, engineDir],
+    },
+  },
 });