refactor: 使用数据库管理龙虾配置

- 创建 Lobster 模型 (lobsters/models.py)
  * name, emoji, port, specialty, container
  * app_name, app_id (外部应用信息)
  * created_at, updated_at (自动时间戳)

- 数据库迁移
  * 创建 lobsters 表
  * 导入 7 只龙虾初始数据

- 更新 API 视图
  * lobster_list: 从数据库读取所有龙虾
  * lobster_detail: 从数据库读取单个龙虾
  * 移除硬编码的 LOBSTERS 配置

- 注册 lobsters 应用到 settings.py

优势:
✅ 添加龙虾不需要改代码
✅ 可通过 Django Admin 管理
✅ 支持动态增删改查
✅ 符合 Django 最佳实践

🦄 白泽成为第 7 只数据库龙虾！

code/backend/lobsters/apps.py

@@ -0,0 +1,6 @@
+from django.apps import AppConfig
+
+
+class LobstersConfig(AppConfig):
+    default_auto_field = 'django.db.models.BigAutoField'
+    name = 'lobsters'

code/backend/lobsters/migrations/0001_initial.py

@@ -0,0 +1,57 @@
+# Generated by Django 4.2 on 2026-04-02 11:16
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = []
+
+    operations = [
+        migrations.CreateModel(
+            name="Lobster",
+            fields=[
+                (
+                    "id",
+                    models.BigAutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+                ("name", models.CharField(max_length=50, verbose_name="名称")),
+                ("emoji", models.CharField(max_length=10, verbose_name="Emoji")),
+                ("port", models.IntegerField(verbose_name="端口")),
+                ("specialty", models.CharField(max_length=100, verbose_name="专长")),
+                ("container", models.CharField(max_length=100, verbose_name="容器")),
+                (
+                    "app_name",
+                    models.CharField(
+                        blank=True, default="", max_length=100, verbose_name="应用名称"
+                    ),
+                ),
+                (
+                    "app_id",
+                    models.CharField(
+                        blank=True, default="", max_length=50, verbose_name="应用 ID"
+                    ),
+                ),
+                (
+                    "created_at",
+                    models.DateTimeField(auto_now_add=True, verbose_name="创建时间"),
+                ),
+                (
+                    "updated_at",
+                    models.DateTimeField(auto_now=True, verbose_name="更新时间"),
+                ),
+            ],
+            options={
+                "verbose_name": "龙虾",
+                "verbose_name_plural": "龙虾",
+                "ordering": ["id"],
+            },
+        ),
+    ]

code/backend/lobsters/models.py

@@ -0,0 +1,21 @@
+from django.db import models
+
+class Lobster(models.Model):
+    """龙虾模型"""
+    name = models.CharField(max_length=50, verbose_name='名称')
+    emoji = models.CharField(max_length=10, verbose_name='Emoji')
+    port = models.IntegerField(verbose_name='端口')
+    specialty = models.CharField(max_length=100, verbose_name='专长')
+    container = models.CharField(max_length=100, verbose_name='容器')
+    app_name = models.CharField(max_length=100, blank=True, default='', verbose_name='应用名称')
+    app_id = models.CharField(max_length=50, blank=True, default='', verbose_name='应用 ID')
+    created_at = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')
+    updated_at = models.DateTimeField(auto_now=True, verbose_name='更新时间')
+    
+    class Meta:
+        verbose_name = '龙虾'
+        verbose_name_plural = '龙虾'
+        ordering = ['id']
+    
+    def __str__(self):
+        return f'{self.emoji} {self.name}'