refactor: 重构 schemas 结构，统一枚举定义

backend/src/models/group_members.py

@@ -1,30 +1,20 @@
 from __future__ import annotations
 
 import uuid
-from enum import Enum
 
 from sqlalchemy import String
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.orm import Mapped, mapped_column
 
 from core.db.base import Base, SoftDeleteMixin, TimestampMixin
+from schemas.enums import GroupMemberRole, GroupMemberSource, GroupMemberStatus
 
-
-class GroupMemberRole(str, Enum):
-    OWNER = "owner"
-    ADMIN = "admin"
-    MEMBER = "member"
-
-
-class GroupMemberSource(str, Enum):
-    INVITED = "invited"
-    JOINED = "joined"
-
-
-class GroupMemberStatus(str, Enum):
-    ACTIVE = "active"
-    MUTED = "muted"
-    REMOVED = "removed"
+__all__ = [
+    "GroupMember",
+    "GroupMemberRole",
+    "GroupMemberSource",
+    "GroupMemberStatus",
+]
 
 
 class GroupMember(TimestampMixin, SoftDeleteMixin, Base):