Improve: Auto-expand parent category and clarify expand/collapse buttons

Improvements to category tree UX:
- Auto-expand parent category after creating subcategory at any nesting level
- Recursive ancestor expansion using elegant DOM traversal with .closest()
- Smooth scroll to newly created category with visual feedback
- Replace icon buttons with text: "Развернуть все" / "Свернуть все"
- Eliminates confusion between "+" for adding category vs expanding tree

Technical implementation:
- URL parameter ?expand=<parent_id> to preserve state after page reload
- Recursive expandAncestors() function traverses up the DOM tree
- Uses :scope selector for precise parent-child relationship queries
- Auto-cleans URL parameter after expansion using history.replaceState()

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

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

myproject/products/templates/products/catalog.html

@@ -151,11 +151,11 @@
             <div class="card shadow-sm border-0 mb-3">
                 <div class="card-header bg-white py-2 d-flex justify-content-between align-items-center">
                     <strong><i class="bi bi-folder-tree text-primary"></i> Категории</strong>
-                    <div class="d-flex gap-2">
+                    <div class="d-flex gap-2 align-items-center">
                         <i class="bi bi-plus-circle text-success cursor-pointer" id="add-root-category-btn" title="Добавить категорию" style="font-size: 1.2rem; cursor: pointer;"></i>
-                        <div class="btn-group btn-group-sm">
-                            <button class="btn btn-outline-secondary btn-sm py-0" id="expand-all" title="Развернуть"><i class="bi bi-plus-square"></i></button>
-                            <button class="btn btn-outline-secondary btn-sm py-0" id="collapse-all" title="Свернуть"><i class="bi bi-dash-square"></i></button>
+                        <div class="d-flex gap-1">
+                            <button class="btn btn-outline-secondary btn-sm" id="expand-all" style="font-size: 0.75rem;">Развернуть</button>
+                            <button class="btn btn-outline-secondary btn-sm" id="collapse-all" style="font-size: 0.75rem;">Свернуть</button>
                         </div>
                     </div>
                 </div>