ver. 0.283: Legacy class cleanup — S, Html, Email, Image, Log, Mobile_Detect → Shared namespace

- Migrate class.S → Shared\Helpers\Helpers (140+ files), remove 12 unused methods
- Migrate class.Html → Shared\Html\Html
- Migrate class.Email → Shared\Email\Email
- Migrate class.Image → Shared\Image\ImageManipulator
- Delete class.Log (unused), class.Mobile_Detect (outdated UA detection)
- Remove grid library loading from admin (index.php, ajax.php)
- Replace gridEdit usage in 10 admin templates with grid-edit-replacement.php
- Fix grid-edit-replacement.php AJAX to send values as JSON (grid.js compat)
- Remove mobile layout conditionals (m_html/m_css/m_js) from Site + LayoutsRepository
- Remove \Log::save_log() calls from OrderAdminService, ShopOrder, Order

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

admin/templates/shop-product/product-combination.php

@@ -22,7 +22,7 @@
                 </tr>
               </thead>
               <tbody>
-                <? if ( \S::is_array_fix( $this -> product_permutations ) ): foreach ( $this -> product_permutations as $product ):?>
+                <? if ( \Shared\Helpers\Helpers::is_array_fix( $this -> product_permutations ) ): foreach ( $this -> product_permutations as $product ):?>
                   <tr data-combination-id="<?= $product['id'];?>">
                     <td>
                       <?