refactor: consolidate all Node.js development into lib package

- Move scripts/ to lib/scripts/ and convert to ESM modules
- Consolidate dependencies: add live-server to lib/package.json
- Remove root package.json and node_modules split
- Preserve CLI integration via existing rebuild-library.sh
- Add development quickstart guide for new unified workflow
- Clean up outdated file references and duplicate assets

lib/package.json

@@ -12,7 +12,12 @@
   "scripts": {
     "build": "rollup -c",
     "watch": "rollup -c -w",
-    "dev": "rollup -c -w"
+    "dev": "rollup -c -w",
+    "serve": "node scripts/dev.js serve",
+    "serve:about": "live-server ../demo-site --port=3000 --open=/about.html",
+    "check": "node scripts/dev.js check",
+    "demo": "node scripts/dev.js demo",
+    "build:all": "node scripts/build.js"
   },
   "keywords": [
     "cms",
@@ -25,6 +30,7 @@
   "devDependencies": {
     "@rollup/plugin-node-resolve": "^15.0.0",
     "@rollup/plugin-terser": "^0.4.0",
-    "rollup": "^3.0.0"
+    "rollup": "^3.0.0",
+    "live-server": "^1.2.2"
   }
 }