LLM-26485: simplify build command

Author: AlexandrSuhinin

build.mjs

@@ -0,0 +1,14 @@
+import { build } from 'esbuild';
+
+await build({
+  entryPoints: ['src/index.ts'],
+  bundle: true,
+  platform: 'node',
+  format: 'esm',
+  outfile: 'dist/index.js',
+  external: ['@openai/codex'],
+  // Polyfill `require` for CJS modules bundled into ESM output
+  banner: {
+    js: "import { createRequire as __createRequire } from 'module'; const require = __createRequire(import.meta.url);",
+  },
+});

package.json

@@ -14,7 +14,7 @@
   ],
   "scripts": {
     "prepublishOnly": "npm run build",
-    "build": "esbuild src/index.ts --bundle --platform=node --format=esm --outfile=dist/index.js --external:@openai/codex --banner:js=\"import { createRequire as __createRequire } from 'module'; const require = __createRequire(import.meta.url);\"",
+    "build": "node build.mjs",
     "bundle:all": "npm run bundle:linux-x64 && npm run bundle:linux-arm64 && npm run bundle:darwin-x64 && npm run bundle:darwin-arm64 && npm run bundle:win-x64",
     "bundle:linux-x64": "bun build src/index.ts --minify --sourcemap --compile --target=bun-linux-x64-baseline --outfile dist/bin/codex-acp-x64-linux",
     "bundle:linux-arm64": "bun build src/index.ts --minify --sourcemap --compile --target=bun-linux-arm64 --outfile dist/bin/codex-acp-arm64-linux",