fix(ui): generate Monaco public assets in dev

packages/ui/vite.config.ts

@@ -7,13 +7,7 @@ import { resolve } from "path"
 const uiPackageJson = JSON.parse(fs.readFileSync(resolve(__dirname, "package.json"), "utf-8")) as { version?: string }
 const uiVersion = uiPackageJson.version ?? "0.0.0"
 
-export default defineConfig({
+function copyMonacoPublicAssets(opts: { warn: (message: string) => void }) {
-  root: "./src/renderer",
-  plugins: [
-    solid(),
-    {
-      name: "prepare-monaco-public-assets",
-      buildStart() {
   const publicDir = resolve(__dirname, "src/renderer/public")
   const destRoot = resolve(publicDir, "monaco/vs")
 
@@ -23,7 +17,7 @@ export default defineConfig({
   ]
   const sourceRoot = candidates.find((p) => fs.existsSync(resolve(p, "loader.js")))
   if (!sourceRoot) {
-          this.warn("Monaco source directory not found; skipping copy")
+    opts.warn("Monaco source directory not found; skipping copy")
     return
   }
 
@@ -56,6 +50,7 @@ export default defineConfig({
       copyRecursive(src, resolve(destRoot, dir))
     }
   }
+
   // loader.js is required.
   copyRecursive(resolve(sourceRoot, "loader.js"), resolve(destRoot, "loader.js"))
 
@@ -84,6 +79,21 @@ export default defineConfig({
   if (fs.existsSync(underscoreContribution)) {
     copyRecursive(underscoreContribution, resolve(destRoot, "basic-languages", "_.contribution.js"))
   }
+}
+
+export default defineConfig({
+  root: "./src/renderer",
+  plugins: [
+    solid(),
+    {
+      name: "prepare-monaco-public-assets",
+      // Ensure Monaco's AMD assets exist in `root/public` for both dev server and builds.
+      // These files are gitignored and generated on demand.
+      configureServer(server) {
+        copyMonacoPublicAssets({ warn: (msg) => server.config.logger.warn(msg) })
+      },
+      buildStart() {
+        copyMonacoPublicAssets({ warn: (msg) => this.warn(msg) })
       },
     },
     {