feat: Page Editor Phase 3 - SSR integration and navigation

- Implement serve_ssr_content with full PageSSR rendering
  - SEO meta tags (title, description, og:*)
  - Minimal CSS for bot-friendly presentation
  - Yoast/Rank Math SEO data integration
- Add maybe_serve_ssr_for_bots hook (priority 2 on template_redirect)
  - Serves SSR for structural pages with WooNooW structure
  - Serves SSR for CPT items with templates
- Add use statements for PageSSR and PlaceholderRenderer
- Add Pages link to Appearance submenu in NavigationRegistry
- Bump NAV_VERSION to 1.1.0

includes/Compat/NavigationRegistry.php

@@ -13,7 +13,7 @@ if ( ! defined('ABSPATH') ) exit;
  */
 class NavigationRegistry {
     const NAV_OPTION = 'wnw_nav_tree';
-    const NAV_VERSION = '1.0.9'; // Added Help menu
+    const NAV_VERSION = '1.1.0'; // Added Pages (Page Editor)
     
     /**
      * Initialize hooks
@@ -169,6 +169,7 @@ class NavigationRegistry {
                 'icon'     => 'palette',
                 'children' => [
                     ['label' => __('General', 'woonoow'), 'mode' => 'spa', 'path' => '/appearance/general'],
+                    ['label' => __('Pages', 'woonoow'), 'mode' => 'spa', 'path' => '/appearance/pages'],
                     ['label' => __('Header', 'woonoow'), 'mode' => 'spa', 'path' => '/appearance/header'],
                     ['label' => __('Footer', 'woonoow'), 'mode' => 'spa', 'path' => '/appearance/footer'],
                     ['label' => __('Shop', 'woonoow'), 'mode' => 'spa', 'path' => '/appearance/shop'],