Fix demo site auto-enhancement and content persistence

- Restructure demo directory from test-sites/ to demos/ with flattened layout
- Add auto-enhancement on server startup for all sites with auto_enhance: true
- Fix inconsistent content ID generation that prevented dan-eden-portfolio content persistence
- Update server configuration to enhance from source to separate output directories
- Remove manual enhancement from justfile in favor of automatic server enhancement
- Clean up legacy test files and unused restore command
- Update build system to use CDN endpoint instead of file copying

lib/rollup.config.js

@@ -2,20 +2,7 @@ import { nodeResolve } from '@rollup/plugin-node-resolve';
 import terser from '@rollup/plugin-terser';
 import { execSync } from 'child_process';
 
-// Simple copy plugin to auto-copy to demo-site during development
-function copyToDemo() {
-  return {
-    name: 'copy-to-demo',
-    writeBundle() {
-      try {
-        execSync('cp dist/insertr.js ../test-sites/demo-site/insertr.js');
-        console.log('📄 Copied to test-sites/demo-site/insertr.js');
-      } catch (error) {
-        console.warn('⚠️  Failed to copy to test-sites/demo-site:', error.message);
-      }
-    }
-  };
-}
+// No longer needed - insertr.js served via CDN endpoint
 
 export default [
   // Development build
@@ -27,8 +14,7 @@ export default [
       name: 'Insertr'
     },
     plugins: [
-      nodeResolve(),
-      copyToDemo()
+      nodeResolve()
     ]
   },
   // Production build (minified)