refactor: 重构 schemas 结构，统一枚举定义

backend/src/models/schedule_subscriptions.py

@@ -1,33 +1,20 @@
 from __future__ import annotations
 
 import uuid
-from enum import Enum
 
 from sqlalchemy import Integer, String
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.orm import Mapped, mapped_column
 
 from core.db.base import Base, TimestampMixin
+from schemas.enums import NotifyLevel, SubscriptionPermission, SubscriptionStatus
 
-
-class SubscriptionStatus(str, Enum):
-    ACTIVE = "active"
-    PENDING = "pending"
-    PAUSED = "paused"
-    UNSUBSCRIBED = "unsubscribed"
-
-
-class NotifyLevel(str, Enum):
-    ALL = "all"
-    MENTIONS = "mentions"
-    NONE = "none"
-
-
-class SubscriptionPermission(int, Enum):
-    VIEW = 1  # 001 - 可查看
-    INVITE = 2  # 010 - 可邀请
-    EDIT = 4  # 100 - 可编辑
-    OWNER = 7  # 111 - 所有者（VIEW + INVITE + EDIT）
+__all__ = [
+    "ScheduleSubscription",
+    "SubscriptionStatus",
+    "NotifyLevel",
+    "SubscriptionPermission",
+]
 
 
 class ScheduleSubscription(TimestampMixin, Base):