feat: replace color field with colors ManyToManyField in items model

- Updated `Item` model to use a ManyToManyField for colors, replacing the old ForeignKey relationship
- Modified templates to handle multiple color swatches in product details
- Updated admin for managing colors with `filter_horizontal`
- Adjusted views to prefetch related `colors` data for items
- Added migration to apply database changes

templates/catalog/detail.html

@@ -56,16 +56,19 @@
                 </span>
             </div>
 
-            {% if item.color %}
-                <div class="product-summary__swatches" aria-label="Цвет товара">
-                    <span
-                        class="product-summary__swatch product-summary__swatch--active"
-                        style="background: {{ item.color.hex_code }};"
-                        title="{{ item.color.name }}"
-                    ></span>
-                    <span class="product-summary__color-name">{{ item.color.name }}</span>
+            {% with colors=item.colors.all %}
+            {% if colors %}
+                <div class="product-summary__swatches" aria-label="Цвета товара">
+                    {% for color in colors %}
+                        <span
+                            class="product-summary__swatch"
+                            style="background: {{ color.hex_code }};"
+                            title="{{ color.name }}"
+                        ></span>
+                    {% endfor %}
                 </div>
             {% endif %}
+            {% endwith %}
 
             {% if item.description %}
                 <div class="product-summary__description">{{ item.description|linebreaksbr }}</div>
@@ -101,3 +104,11 @@
 
     {% include "_fragments/footer.html" %}
 {% endblock %}
+
+{% block add_js %}
+<script>
+    document.addEventListener('DOMContentLoaded', function () {
+        Fancybox.bind('[data-fancybox="product-gallery"]');
+    });
+</script>
+{% endblock %}