feat: 目标和问题统一分类体系(综合/乐理相关/演奏能力/其他)，添加数据库迁移

app/routes/goals.py

@@ -25,7 +25,8 @@ def create_goal():
     goal = Goal(
         name=data["name"],
         content=data.get("content", ""),
-        level=data.get("level", "入门")
+        level=data.get("level", "入门"),
+        category=data.get("category", "综合")
     )
     db.session.add(goal)
     db.session.commit()
@@ -48,6 +49,8 @@ def update_goal(goal_id):
         goal.content = data["content"]
     if "level" in data:
         goal.level = data["level"]
+    if "category" in data:
+        goal.category = data["category"]
     db.session.commit()
     return jsonify(goal.to_dict())