feat: add color, discount price, and new item attributes to catalog and update UI

- Introduced `Color` model with admin and added a color field to items
- Added `discount_price` and `is_new` fields to the `Item` model with necessary migrations
- Updated pricing logic to display original and discount prices in templates
- Enhanced product detail and item card templates with color swatches and metadata
- Added sidebar sections for sales and new items with paginated mini-cards
- Updated styles to support discount pricing, swatches, and sidebar mini-cards
- Extended catalog views to filter by sales or new items and updated filtering logic

templates/catalog/_fragments/item-card.html

@@ -48,7 +48,14 @@
             <h2 class="item-card-title">{{ item.name }}</h2>
         </a>
         <div class="item-card-footer">
-            <span class="item-card-price">{{ item.price }} руб.</span>
+            <div class="item-card-price-block">
+                <span class="item-card-price{% if item.has_discount %} item-card-price--discount{% endif %}">
+                    {{ item.display_price }} руб.
+                </span>
+                {% if item.has_discount %}
+                    <span class="item-card-price-original">{{ item.price }} руб.</span>
+                {% endif %}
+            </div>
             <span class="item-card-availability {% if item.is_available %}available{% else %}unavailable{% endif %}">
                 {% if item.is_available %}В наличии{% else %}Нет в наличии{% endif %}
             </span>

templates/catalog/_fragments/side-bar.html

@@ -34,6 +34,12 @@
         {% if selected_subcategory.id != None %}
             <input type="hidden" name="subcategory" value="{{ selected_subcategory.id }}">
         {% endif %}
+        {% if filter_sale %}
+            <input type="hidden" name="sale" value="1">
+        {% endif %}
+        {% if filter_new %}
+            <input type="hidden" name="new" value="1">
+        {% endif %}
         <section class="a-section cost-section">
             <h2>Стоимость</h2>
             <div
@@ -86,13 +92,57 @@
         <section class="a-section material-section">
             <h2>Материал</h2>
         </section>
-
-        <section class="a-section promotions-section">
-            <h2>Акции</h2>
-        </section>
-
-        <section class="a-section new-section">
-            <h2>Новинки</h2>
-        </section>
     </form>
+
+    <section class="a-section promotions-section">
+        <h2>
+            <a href="{{ sale_all_url }}" class="sidebar-section-link{% if filter_sale %} active{% endif %}">Акции</a>
+        </h2>
+        {% for sale_item in sidebar_sale_items %}
+            <div class="sidebar-mini-card">
+                {% with img=sale_item.primary_image %}
+                    {% if img %}
+                        <a href="{% url 'detail' sale_item.category.slug sale_item.slug %}" class="sidebar-mini-card__img-link">
+                            <img src="{{ img.image.url }}" alt="{{ img.alt|default:sale_item.name }}">
+                        </a>
+                    {% endif %}
+                {% endwith %}
+                <div class="sidebar-mini-card__body">
+                    <a href="{% url 'detail' sale_item.category.slug sale_item.slug %}" class="sidebar-mini-card__name">{{ sale_item.name }}</a>
+                    <span class="sidebar-mini-card__price">{{ sale_item.display_price }} руб.</span>
+                </div>
+            </div>
+        {% empty %}
+            <p class="categories-empty">Акций пока нет.</p>
+        {% endfor %}
+        {% if sidebar_sale_items %}
+            <a href="{{ sale_all_url }}" class="sidebar-more-link">Ещё</a>
+        {% endif %}
+    </section>
+
+    <section class="a-section new-section">
+        <h2>
+            <a href="{{ new_all_url }}" class="sidebar-section-link{% if filter_new %} active{% endif %}">Новинки</a>
+        </h2>
+        {% for new_item in sidebar_new_items %}
+            <div class="sidebar-mini-card">
+                {% with img=new_item.primary_image %}
+                    {% if img %}
+                        <a href="{% url 'detail' new_item.category.slug new_item.slug %}" class="sidebar-mini-card__img-link">
+                            <img src="{{ img.image.url }}" alt="{{ img.alt|default:new_item.name }}">
+                        </a>
+                    {% endif %}
+                {% endwith %}
+                <div class="sidebar-mini-card__body">
+                    <a href="{% url 'detail' new_item.category.slug new_item.slug %}" class="sidebar-mini-card__name">{{ new_item.name }}</a>
+                    <span class="sidebar-mini-card__price">{{ new_item.display_price }} руб.</span>
+                </div>
+            </div>
+        {% empty %}
+            <p class="categories-empty">Новинок пока нет.</p>
+        {% endfor %}
+        {% if sidebar_new_items %}
+            <a href="{{ new_all_url }}" class="sidebar-more-link">Ещё</a>
+        {% endif %}
+    </section>
 </aside>