ci: stage desktop runtime without root tsdown entry

Author: Shaw

packages/app-core/scripts/desktop-build.mjs

@@ -516,13 +516,42 @@ function findLatestMacAppBundle() {
   return candidates[0].appBundlePath;
 }
 
+function hasRootTsdownEntry() {
+  return (
+    fs.existsSync(path.join(ROOT, "tsdown.config.ts")) ||
+    fs.existsSync(path.join(ROOT, "tsdown.config.mts")) ||
+    fs.existsSync(path.join(ROOT, "tsdown.config.js")) ||
+    fs.existsSync(path.join(ROOT, "src", "index.ts"))
+  );
+}
+
+function ensureRootRuntimeBundle() {
+  if (hasRootTsdownEntry()) {
+    runPackageBinary("tsdown", [], {
+      cwd: ROOT,
+      label: "Building core runtime bundle with tsdown",
+    });
+    return;
+  }
+
+  const distDir = path.join(ROOT, "dist");
+  const entrySource = [
+    "// auto-generated by desktop-build.mjs",
+    "// Standalone elizaOS checkouts do not have a root tsdown entry.",
+    'export * from "../packages/app-core/src/entry.ts";',
+    "",
+  ].join("\n");
+
+  fs.mkdirSync(distDir, { recursive: true });
+  fs.writeFileSync(path.join(distDir, "entry.js"), entrySource);
+  fs.writeFileSync(path.join(distDir, "index.js"), entrySource);
+  fs.writeFileSync(path.join(distDir, "package.json"), '{"type":"module"}\n');
+}
+
 function stageDesktopBuild() {
   ensureAppDirs();
 
-  runPackageBinary("tsdown", [], {
-    cwd: ROOT,
-    label: "Building core runtime bundle with tsdown",
-  });
+  ensureRootRuntimeBundle();
 
   runNode(["--import", "tsx", "scripts/write-build-info.ts"], {
     cwd: ROOT,