feat: threads

vite.config.ts

@@ -1,8 +1,24 @@
 import { defineConfig } from "vite"
 
+// Cross-origin isolation (COOP + COEP) is required for SharedArrayBuffer, which
+// the multi-threaded renderer uses to share the framebuffer across workers.
+// Without these headers the app still runs -- it falls back to single-threaded.
+const crossOriginIsolation = {
+  "Cross-Origin-Opener-Policy": "same-origin",
+  "Cross-Origin-Embedder-Policy": "require-corp",
+}
+
 export default defineConfig({
   resolve: {
     tsconfigPaths: true,
   },
+  worker: {
+    format: "es",
+  },
+  server: {
+    headers: crossOriginIsolation,
+  },
+  preview: {
+    headers: crossOriginIsolation,
+  },
 })
-