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- Clean up outdated file references and duplicate assets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/src/core/auth.js

@@ -509,16 +509,16 @@ export class InsertrAuth {
             }
 
             /* Hide editing interface when not in edit mode */
-            body:not(.insertr-edit-mode) [data-insertr-enhanced]:hover::after {
+            body:not(.insertr-edit-mode) .insertr:hover::after {
                 display: none !important;
             }
 
             /* Only show editing features when in edit mode */
-            .insertr-authenticated.insertr-edit-mode [data-insertr-enhanced] {
+            .insertr-authenticated.insertr-edit-mode .insertr {
                 cursor: pointer;
             }
 
-            .insertr-authenticated.insertr-edit-mode [data-insertr-enhanced]:hover {
+            .insertr-authenticated.insertr-edit-mode .insertr:hover {
                 outline: 2px dashed #007cba !important;
                 outline-offset: 2px !important;
                 background-color: rgba(0, 124, 186, 0.05) !important;

lib/src/core/editor.js

@@ -130,7 +130,7 @@ export class InsertrEditor {
                 background-color: rgba(0, 124, 186, 0.05) !important;
             }
             
-            [data-insertr-enhanced="true"]:hover::after {
+            .insertr:hover::after {
                 content: "✏️ " attr(data-content-type);
                 position: absolute;
                 top: -25px;

lib/src/core/insertr.js

@@ -12,7 +12,7 @@ export class InsertrCore {
     
     // Find all enhanced elements on the page
     findEnhancedElements() {
-        return document.querySelectorAll('[data-insertr-enhanced="true"]');
+        return document.querySelectorAll('.insertr');
     }
     
     // Get element metadata