fix(run): add missing binary check for lark-cli execution (#362)

scripts/run.js

@@ -3,11 +3,25 @@
 // SPDX-License-Identifier: MIT
 
 const { execFileSync } = require("child_process");
+const fs = require("fs");
 const path = require("path");
 
 const ext = process.platform === "win32" ? ".exe" : "";
 const bin = path.join(__dirname, "..", "bin", "lark-cli" + ext);
 
+if (!fs.existsSync(bin)) {
+  console.error(
+    `Error: lark-cli binary not found at ${bin}\n\n` +
+    `This usually means the postinstall script was skipped.\n` +
+    `Common causes:\n` +
+    `  - npm is configured with ignore-scripts=true\n` +
+    `  - The postinstall download failed\n\n` +
+    `To fix, run the install script manually:\n` +
+    `  node "${path.join(__dirname, "install.js")}"\n`
+  );
+  process.exit(1);
+}
+
 try {
   execFileSync(bin, process.argv.slice(2), { stdio: "inherit" });
 } catch (e) {