feat(js): switch to eager loading to eliminate layout shift

Instead of lazy loading slots when they enter the viewport (which
causes layout shift when unfilled slots collapse), now all slots
are activated immediately on page load.

- Slots start collapsed (max-height:0, opacity:0) via CSS
- All slots are activated with 100ms stagger to avoid rate limiting
- Only slots confirmed as 'filled' expand and become visible
- Unfilled slots remain collapsed - zero layout shift

This completely eliminates the CLS issue where content would jump
when ad slots were hidden after entering the viewport.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

functions.php

@@ -18,7 +18,7 @@ if (!defined('ABSPATH')) {
 }
 
 // Definir constante de versión del tema
-define('ROI_VERSION', '1.0.25');
+define('ROI_VERSION', '1.0.26');
 
 // =============================================================================
 // 1. CARGAR AUTOLOADER MANUAL