chore: configure codex build environment

manifest.llm.json

@@ -5,6 +5,11 @@
   "project_type": "chrome-extension",
   "language": "typescript",
   "package_manager": "npm",
+  "deployable_output": {
+    "path": "dist/",
+    "type": "chrome-extension",
+    "description": "Build output is self-contained and can be loaded directly as an unpacked Chrome extension."
+  },
   "entrypoints": {
     "popup_html": "index.html",
     "popup_script": "src/main.ts",
@@ -14,10 +19,14 @@
     "generated_manifest": "dist/manifest.json"
   },
   "commands": {
-    "install": "npm install",
+    "install": "npm ci",
+    "codex_setup": "npm run codex:setup",
     "dev": "npm run dev",
+    "codex_dev": "npm run dev:codex",
     "build": "npm run build",
-    "preview": "npm run preview"
+    "codex_build": "npm run build:codex",
+    "preview": "npm run preview",
+    "verify_dist": "npm run verify:dist"
   },
   "environment": {
     "example_file": ".env.example",