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- Delete class.Log (unused), class.Mobile_Detect (outdated UA detection)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>

templates/shop-producer/list.php

@@ -1,7 +1,7 @@
 <div class="producer-list">
   <? foreach ( $this -> producers as $producer ):?>
     <div class="producer">
-      <a href="/producent/<?= \S::seo( $producer['name'] );?>">
+      <a href="/producent/<?= \Shared\Helpers\Helpers::seo( $producer['name'] );?>">
         <? if ( file_exists( substr( $producer['img'], 1, strlen( $producer['img'] ) ) ) ):?>
           <img src="<?= $producer['img'];?>" alt="<?= $producer['name'];?>">
         <? endif;?>