feat: add favorites feature for users

- Implemented `Favorite` model with unique user-item constraint and timestamped records
- Added `favorites:index` and `favorites:toggle` views with AJAX support for toggling favorites
- Built templates and front-end assets for the favorites page and integration with item grids
- Extended header with favorites link and dynamic counter
- Added tests covering models, views, and templates for the favorites functionality
- Updated admin to enable management of favorites via Django admin interface

favorites/migrations/0001_initial.py

@@ -0,0 +1,33 @@
+# Generated by Django 6.0.4 on 2026-05-10 17:49
+
+import django.db.models.deletion
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+        ('items', '0003_subcategory_item_subcategory_and_more'),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Favorite',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('created_at', models.DateTimeField(auto_now_add=True, verbose_name='Дата добавления')),
+                ('item', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='favorite_entries', to='items.item', verbose_name='Товар')),
+                ('user', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='favorite_entries', to=settings.AUTH_USER_MODEL, verbose_name='Пользователь')),
+            ],
+            options={
+                'verbose_name': 'Избранный товар',
+                'verbose_name_plural': 'Избранные товары',
+                'ordering': ('-created_at', '-id'),
+                'constraints': [models.UniqueConstraint(fields=('user', 'item'), name='unique_favorite_user_item')],
+            },
+        ),
+    ]

favorites/migrations/__init__.py

@@ -0,0 +1 @@
+