fix: button detection with text alignment

Added data-button attribute selector to TipTap button parseHTML.
This ensures buttons are properly detected when text alignment is
applied, as alignment may affect CSS class detection.

Priority order:
1. a[data-button] - most reliable
2. a.button
3. a.button-outline

admin-spa/src/components/ui/tiptap-button-extension.ts

@@ -37,6 +37,9 @@ export const ButtonExtension = Node.create<ButtonOptions>({
 
   parseHTML() {
     return [
+      {
+        tag: 'a[data-button]',
+      },
       {
         tag: 'a.button',
       },