perf: 性能与资源优化 - 提取内联资源、数据库查询优化、限流与缓存增强

主要优化:
- templates/index.html: 220KB → 28KB，内联CSS/JS提取为静态文件
- menu/serializers.py: 修复 Order.ingredients_summary N+1 查询问题
- menu/services/dish_service.py: 移除多余查询，添加 only() 限制字段
- menu/views.py: 上传接口添加每分钟20次限流
- static/js/api.js: 统一API错误处理
- zhangmenu/settings.py: 添加Whitenoise压缩、Redis缓存支持、环境变量配置
- static/css/app.css, static/js/app.js: 提取的内联资源文件
- 新增 migrations, requirements.txt, .env.example

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

menu/admin.py

@@ -1,3 +1,26 @@
 from django.contrib import admin
+from .models import Dish, DishCategory, Order
 
-# Register your models here.
+
+@admin.register(DishCategory)
+class DishCategoryAdmin(admin.ModelAdmin):
+    list_display = ['id', 'name', 'icon', 'order']
+    list_editable = ['name', 'icon', 'order']
+    search_fields = ['name']
+
+
+@admin.register(Dish)
+class DishAdmin(admin.ModelAdmin):
+    list_display = ['id', 'name', 'category', 'view_count', 'created_at']
+    list_filter = ['category', 'created_at']
+    search_fields = ['name', 'description']
+    raw_id_fields = ['category']
+
+
+@admin.register(Order)
+class OrderAdmin(admin.ModelAdmin):
+    list_display = ['id', 'name', 'status', 'party_date', 'created_at', 'completed_at']
+    list_filter = ['status', 'created_at']
+    search_fields = ['name', 'note']
+    readonly_fields = ['created_at', 'completed_at']
+    filter_horizontal = ['dishes']