feat(hotelGroups): add offer display fields and related logic

- Add new database columns (coverImage, priceAmount, priceUnit, tags, status) to HotelGroup model
- Create hotel_group_dict serializer to handle image/coverImage synchronization and tag formatting
- Update site config endpoints to use the new serializer and filter published hotel groups
- Add Alembic migration for the new database schema changes
- Update test fixtures and API contract tests for the new fields
- Revise public and admin API documentation to document the new hotel group fields and usage rules

app/seed.py

@@ -145,6 +145,12 @@ def reset_guizhou_content(db: Session) -> dict:
                 title=group["title"],
                 description=group.get("description"),
                 image=group.get("image"),
+                coverImage=group.get("coverImage") or group.get("image"),
+                priceAmount=group.get("priceAmount"),
+                priceUnit=group.get("priceUnit") or "起/晚",
+                tags=group.get("tags", []),
+                status=group.get("status", "published"),
+                isActive=group.get("isActive", True),
                 sortOrder=index,
             )
         )