feat: add hotel and vehicle option site modules

Add full support for hotel group and vehicle option site management features:
- Define SQLAlchemy models and alembic migration for the new database tables
- Add default sample content entries in content.py
- Extend admin and public API routes to support the new modules
- Update seed script to populate default hotel and vehicle data
- Update all relevant documentation and test cases

app/content.py

@@ -76,6 +76,32 @@ CTAS = [
     ("提交贵州出行需求", "/assets/guizhou/shuichunhe-rafting.jpg", "demand", None),
 ]
 
+HOTEL_GROUPS = [
+    {
+        "title": "经典酒店",
+        "image": "/assets/guizhou/bailian-hot-spring.jpg",
+        "description": "城市接驳、景区度假和温泉休整，适合首游贵州的小包团动线。",
+    },
+    {
+        "title": "野奢酒店",
+        "image": "/assets/guizhou/jianhe-hot-spring.jpg",
+        "description": "把山地、村寨、星空和温泉留给行程里的慢时刻。",
+    },
+]
+
+VEHICLE_OPTIONS = [
+    {
+        "title": "5座舒适用车",
+        "image": "/assets/guizhou/jiaxiu-tower.jpg",
+        "description": "适合2-4人家庭或好友小团，城市接送、景区穿梭更灵活。",
+    },
+    {
+        "title": "9座精品商务车",
+        "image": "/assets/guizhou/wanfenglin.jpg",
+        "description": "适合5-8人同行、亲子或长辈出行，留足行李和休息空间。",
+    },
+]
+
 CAMPAIGNS = [
     {"slug": "classic-deal", "title": "经典打卡特惠", "start": 0, "end": 8, "coverImage": HERO_SLIDES[0]["image"]},
     {"slug": "outdoor-deal", "title": "山野野咖特惠", "start": 8, "end": 16, "coverImage": HERO_SLIDES[1]["image"]},