feat: add fixed sidebar navigation with hover expand and mobile hamburger

Implements Task 3: fixed left sidebar (70px collapsed → 250px on hover) with
9 nav items, social links, active-state detection, and mobile hamburger toggle
that matches the existing sidebar-nav.js selectors.

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

wp-content/themes/bitwms-child/templates/sidebar-nav.php

@@ -0,0 +1,150 @@
+<?php
+/**
+ * БИТ.WMS Child Theme — Sidebar navigation template
+ *
+ * Fixed left sidebar: collapses to 70px (icons only), expands to 250px on hover.
+ * On mobile (<768px) hidden by default, toggled via .sidebar-nav__toggle button.
+ *
+ * @package bitwms-child
+ */
+
+if ( ! defined( 'ABSPATH' ) ) {
+    exit;
+}
+
+$theme_uri = get_stylesheet_directory_uri();
+
+// Current path for active-state detection.
+$current_path = wp_parse_url( get_permalink(), PHP_URL_PATH );
+if ( empty( $current_path ) ) {
+    $current_path = $_SERVER['REQUEST_URI'] ?? '/';
+}
+
+$nav_items = array(
+    array(
+        'label' => 'БИТ.WMS',
+        'url'   => '/bit-wms/',
+        'icon'  => 'warehouse.svg',
+    ),
+    array(
+        'label' => 'Кейсы',
+        'url'   => '/cases/',
+        'icon'  => 'folder.svg',
+    ),
+    array(
+        'label' => 'Статьи',
+        'url'   => '/articles/',
+        'icon'  => 'document.svg',
+    ),
+    array(
+        'label' => 'Вебинары',
+        'url'   => '/webinars/',
+        'icon'  => 'camera.svg',
+    ),
+    array(
+        'label' => 'Курсы',
+        'url'   => '/courses/',
+        'icon'  => 'graduation.svg',
+    ),
+    array(
+        'label' => 'Мероприятия',
+        'url'   => '/events/',
+        'icon'  => 'calendar.svg',
+    ),
+    array(
+        'label' => 'Материалы',
+        'url'   => '/materials/',
+        'icon'  => 'download.svg',
+    ),
+    array(
+        'label' => 'Новости',
+        'url'   => '/news/',
+        'icon'  => 'bell.svg',
+    ),
+    array(
+        'label' => 'Контакты',
+        'url'   => '/contacts/',
+        'icon'  => 'phone.svg',
+    ),
+);
+?>
+
+<button class="sidebar-nav__toggle" aria-label="<?php esc_attr_e( 'Открыть меню', 'bitwms-child' ); ?>" aria-expanded="false">
+    <span class="sidebar-nav__toggle-bar"></span>
+    <span class="sidebar-nav__toggle-bar"></span>
+    <span class="sidebar-nav__toggle-bar"></span>
+</button>
+
+<aside class="sidebar-nav" aria-label="<?php esc_attr_e( 'Основная навигация', 'bitwms-child' ); ?>">
+
+    <div class="sidebar-nav__logo">
+        <a href="<?php echo esc_url( home_url( '/' ) ); ?>" aria-label="<?php esc_attr_e( 'На главную', 'bitwms-child' ); ?>">
+            <img
+                src="<?php echo esc_url( $theme_uri . '/img/logo-short.svg' ); ?>"
+                alt="<?php esc_attr_e( 'БИТ.WMS', 'bitwms-child' ); ?>"
+                width="32"
+                height="32"
+            />
+        </a>
+    </div>
+
+    <nav class="sidebar-nav__menu" aria-label="<?php esc_attr_e( 'Разделы сайта', 'bitwms-child' ); ?>">
+        <ul class="sidebar-nav__list">
+            <?php foreach ( $nav_items as $item ) :
+                $is_active   = rtrim( $current_path, '/' ) === rtrim( $item['url'], '/' );
+                $item_class  = 'sidebar-nav__item' . ( $is_active ? ' sidebar-nav__item--active' : '' );
+                $icon_src    = esc_url( $theme_uri . '/img/icons/' . $item['icon'] );
+            ?>
+            <li class="<?php echo esc_attr( $item_class ); ?>">
+                <a
+                    href="<?php echo esc_url( $item['url'] ); ?>"
+                    class="sidebar-nav__link"
+                    <?php if ( $is_active ) : ?>aria-current="page"<?php endif; ?>
+                >
+                    <img
+                        class="sidebar-nav__icon"
+                        src="<?php echo $icon_src; ?>"
+                        alt=""
+                        width="24"
+                        height="24"
+                        aria-hidden="true"
+                    />
+                    <span class="sidebar-nav__label"><?php echo esc_html( $item['label'] ); ?></span>
+                </a>
+            </li>
+            <?php endforeach; ?>
+        </ul>
+    </nav>
+
+    <div class="sidebar-nav__social">
+        <a
+            href="https://t.me/bitwms"
+            class="sidebar-nav__social-link"
+            target="_blank"
+            rel="noopener noreferrer"
+            aria-label="<?php esc_attr_e( 'Telegram', 'bitwms-child' ); ?>"
+        >
+            <img
+                src="<?php echo esc_url( $theme_uri . '/img/icons/telegram.svg' ); ?>"
+                alt="Telegram"
+                width="24"
+                height="24"
+            />
+        </a>
+        <a
+            href="https://vk.com/bitwms"
+            class="sidebar-nav__social-link"
+            target="_blank"
+            rel="noopener noreferrer"
+            aria-label="<?php esc_attr_e( 'ВКонтакте', 'bitwms-child' ); ?>"
+        >
+            <img
+                src="<?php echo esc_url( $theme_uri . '/img/icons/vk.svg' ); ?>"
+                alt="ВКонтакте"
+                width="24"
+                height="24"
+            />
+        </a>
+    </div>
+
+</aside>