Add stock availability display to product list and detail views

- Add total_available, total_reserved, total_free annotations to product queries
- Display free stock (green/red) with reserved count in product list
- Show detailed stock info in product detail page (moved to top)
- Make reservation count clickable to view filtered reservations
- Add product filter support to ReservationListView
- Add product link in reservation list for easy navigation

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

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

myproject/products/templates/products/product_detail.html

@@ -139,6 +139,16 @@
                             <th>Артикул:</th>
                             <td>{{ product.sku }}</td>
                         </tr>
+                        <tr>
+                            <th>Остаток:</th>
+                            <td>
+                                <strong class="fs-5 {% if product.total_free > 0 %}text-success{% else %}text-danger{% endif %}">{{ product.total_free|floatformat:0 }}</strong> <span class="text-muted">свободно</span>
+                                {% if product.total_reserved > 0 %}
+                                    <a href="{% url 'inventory:reservation-list' %}?product={{ product.pk }}" class="ms-2 text-warning text-decoration-none" target="_blank" title="Посмотреть резервы"><i class="bi bi-lock"></i> {{ product.total_reserved|floatformat:0 }} в резерве <i class="bi bi-box-arrow-up-right small"></i></a>
+                                {% endif %}
+                                <span class="ms-2 text-muted small">(всего: {{ product.total_available|floatformat:0 }})</span>
+                            </td>
+                        </tr>
                         <tr>
                             <th>Описание:</th>
                             <td>{{ product.description|default:"-" }}</td>
@@ -266,16 +276,6 @@
                                 {% endif %}
                             </td>
                         </tr>
-                        <tr>
-                            <th>В наличии:</th>
-                            <td>
-                                {% if product.in_stock %}
-                                    <span class="badge bg-success"><i class="bi bi-check-circle"></i> Да, в наличии</span>
-                                {% else %}
-                                    <span class="badge bg-danger"><i class="bi bi-x-circle"></i> Нет, закончился</span>
-                                {% endif %}
-                            </td>
-                        </tr>
                         <tr>
                             <th>Статус:</th>
                             <td>

myproject/products/templates/products/products_list.html

@@ -131,7 +131,7 @@
                     <th>Категория</th>
                     <th style="width: 150px;">Теги</th>
                     <th style="width: 130px;">Цена</th>
-                    <th style="width: 100px;">В наличии</th>
+                    <th style="width: 120px;">Остаток</th>
                     <th style="width: 100px;">Статус</th>
                     <th style="width: 150px;">Действия</th>
                 </tr>
@@ -193,10 +193,8 @@
                     </td>
                     <td>
                         {% if item.item_type == 'product' %}
-                            {% if item.in_stock %}
-                                <span class="badge bg-success"><i class="bi bi-check-circle"></i> Да</span>
-                            {% else %}
-                                <span class="badge bg-danger"><i class="bi bi-x-circle"></i> Нет</span>
+                            <strong class="{% if item.total_free > 0 %}text-success{% else %}text-danger{% endif %}">{{ item.total_free|floatformat:0 }}</strong>{% if item.total_reserved > 0 %}<small class="text-muted"> / {{ item.total_available|floatformat:0 }}</small>
+                                <small class="text-warning d-block">{{ item.total_reserved|floatformat:0 }} в резерве</small>
                             {% endif %}
                         {% else %}
                             <span class="text-muted">-</span>

myproject/products/views/product_views.py

@@ -5,7 +5,8 @@ from django.contrib import messages
 from django.contrib.auth.mixins import LoginRequiredMixin, PermissionRequiredMixin
 from django.views.generic import ListView, CreateView, DetailView, UpdateView, DeleteView
 from django.urls import reverse_lazy
-from django.db.models import Q
+from django.db.models import Q, Sum, Value, DecimalField
+from django.db.models.functions import Coalesce
 from itertools import chain
 
 from ..models import Product, ProductCategory, ProductTag, ProductKit
@@ -162,8 +163,14 @@ class ProductDetailView(LoginRequiredMixin, PermissionRequiredMixin, DetailView)
     permission_required = 'products.view_product'
 
     def get_queryset(self):
-        # Предзагрузка фотографий для избежания N+1 запросов
-        return super().get_queryset().prefetch_related('photos')
+        # Предзагрузка фотографий и аннотация остатков
+        total_available = Coalesce(Sum('stocks__quantity_available'), Value(0), output_field=DecimalField())
+        total_reserved = Coalesce(Sum('stocks__quantity_reserved'), Value(0), output_field=DecimalField())
+        return super().get_queryset().prefetch_related('photos').annotate(
+            total_available=total_available,
+            total_reserved=total_reserved,
+            total_free=total_available - total_reserved,
+        )
 
     def get_context_data(self, **kwargs):
         context = super().get_context_data(**kwargs)
@@ -253,7 +260,14 @@ class CombinedProductListView(LoginRequiredMixin, PermissionRequiredMixin, ListV
         type_filter = self.request.GET.get('type', 'all')
         
         # Получаем товары и комплекты (только постоянные комплекты)
-        products = Product.objects.prefetch_related('categories', 'photos', 'tags')
+        # Аннотируем товары данными об остатках из агрегированной таблицы Stock
+        total_available = Coalesce(Sum('stocks__quantity_available'), Value(0), output_field=DecimalField())
+        total_reserved = Coalesce(Sum('stocks__quantity_reserved'), Value(0), output_field=DecimalField())
+        products = Product.objects.prefetch_related('categories', 'photos', 'tags').annotate(
+            total_available=total_available,
+            total_reserved=total_reserved,
+            total_free=total_available - total_reserved,
+        )
         kits = ProductKit.objects.filter(is_temporary=False).prefetch_related('categories', 'photos', 'tags')
 
         # Применяем фильтры