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- Clean up outdated file references and duplicate assets

package.json

@@ -1,46 +0,0 @@
-{
-  "name": "insertr",
-  "version": "0.1.0",
-  "description": "The Tailwind of CMS - Zero-configuration content editing for any static site",
-  "main": "lib/dist/insertr.js",
-  "scripts": {
-    "dev": "node scripts/dev.js serve",
-    "dev:about": "live-server demo-site --port=3000 --open=/about.html",
-    "dev:check": "node scripts/dev.js check",
-    "dev:demo": "node scripts/dev.js demo",
-    "dev:help": "node scripts/dev.js help",
-    "build": "node scripts/build.js",
-    "test": "echo 'Test script placeholder - will add tests for insertr.js'",
-    "lint": "echo 'Linting placeholder - will add ESLint'",
-    "serve": "npm run dev",
-    "start": "npm run dev"
-  },
-  "keywords": [
-    "cms",
-    "headless-cms",
-    "static-site-generator",
-    "content-management",
-    "build-time-enhancement",
-    "zero-config",
-    "go",
-    "javascript"
-  ],
-  "author": "Your Name",
-  "license": "MIT",
-  "repository": {
-    "type": "git",
-    "url": "git+https://github.com/yourusername/insertr.git"
-  },
-  "devDependencies": {
-    "live-server": "^1.2.2"
-  },
-  "engines": {
-    "node": ">=16.0.0",
-    "npm": ">=8.0.0"
-  },
-  "browserslist": [
-    "defaults",
-    "not IE 11"
-  ],
-  "dependencies": {}
-}