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/models.py

@@ -19,7 +19,7 @@ class DishCategory(models.Model):
 class Dish(models.Model):
     """菜品"""
     name = models.CharField(max_length=100, verbose_name="菜品名称")
-    category = models.ForeignKey(DishCategory, on_delete=models.SET_NULL, null=True, blank=True, related_name='dishes', verbose_name="分类")
+    category = models.ForeignKey(DishCategory, on_delete=models.SET_NULL, null=True, blank=True, related_name='dishes', verbose_name="分类", db_index=True)
     cover_image = models.CharField(max_length=500, blank=True, null=True, verbose_name="封面图URL")
     description = models.TextField(blank=True, verbose_name="做法描述(Markdown格式)")
     ingredients = models.JSONField(default=list, verbose_name="材料清单")
@@ -31,6 +31,10 @@ class Dish(models.Model):
         verbose_name = "菜品"
         verbose_name_plural = "菜品"
         ordering = ['-created_at']
+        indexes = [
+            models.Index(fields=['name']),
+            models.Index(fields=['-created_at']),
+        ]
 
     def __str__(self):
         return self.name
@@ -46,7 +50,7 @@ class Order(models.Model):
     name = models.CharField(max_length=100, verbose_name="订单名称")
     dishes = models.ManyToManyField(Dish, related_name='orders', verbose_name="菜品")
     status = models.CharField(max_length=20, choices=STATUS_CHOICES, default='in_progress', verbose_name="状态")
-    party_date = models.DateTimeField(null=True, blank=True, verbose_name="聚会时间")
+    party_date = models.DateTimeField(null=True, blank=True, verbose_name="聚会时间", db_index=True)
     participants = models.JSONField(default=list, verbose_name="参与人员")
     created_at = models.DateTimeField(auto_now_add=True, verbose_name="创建时间")
     completed_at = models.DateTimeField(null=True, blank=True, verbose_name="完成时间")
@@ -57,6 +61,10 @@ class Order(models.Model):
         verbose_name = "订单"
         verbose_name_plural = "订单"
         ordering = ['-created_at']
+        indexes = [
+            models.Index(fields=['status', '-created_at']),
+            models.Index(fields=['party_date']),
+        ]
 
     def __str__(self):
         return self.name