chore: bump asset cache-busting version to 2.0.0

The stylesheets and the module script changed substantially, so the previous
value would have left browsers on the cached 1.x assets after an update.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/Controller/ContentElement/BlatterbaresPdfController.php

@@ -20,7 +20,7 @@ class BlatterbaresPdfController extends AbstractContentElementController
     /**
      * Bumped when the shipped assets change, so browsers do not keep a stale copy.
      */
-    private const ASSET_VERSION = '20260414j';
+    private const ASSET_VERSION = '2.0.0';
 
     public function __construct(
         #[Autowire('%kernel.project_dir%')]