[fix]:[FL-145][系统消息要支持删除]

Co-authored-by: multica-agent <github@multica.ai>

api/app/api/v1/system_messages.py

@@ -3,6 +3,7 @@ from sqlalchemy.orm import Session
 
 from ...core.database import get_db
 from ...core.dependencies import CurrentUser, get_current_user, require_permission
+from ...schemas.auth import MessageResponse
 from ...schemas.system_message import (
     SystemMessageCreateRequest,
     SystemMessageListResponse,
@@ -11,6 +12,7 @@ from ...schemas.system_message import (
 )
 from ...services.system_message_service import (
     create_system_message,
+    delete_system_message,
     get_unread_count,
     list_user_messages,
     mark_messages_as_read,
@@ -72,3 +74,16 @@ def mark_my_messages_read(
     """标记消息为已读"""
     affected = mark_messages_as_read(db, current_user.user.id, payload.message_ids)
     return {"affected": affected}
+
+
+@router.delete("/{message_id}", response_model=MessageResponse)
+def remove_system_message(
+    message_id: str,
+    _: CurrentUser = Depends(require_permission("admin.system_message")),
+    db: Session = Depends(get_db),
+) -> MessageResponse:
+    """删除系统消息（需要admin.system_message权限）"""
+    deleted = delete_system_message(db, message_id)
+    if not deleted:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="System message not found")
+    return MessageResponse(message="System message deleted")

api/app/services/system_message_service.py

@@ -1,7 +1,7 @@
 from datetime import datetime
 from typing import TYPE_CHECKING
 
-from sqlalchemy import func, select, update
+from sqlalchemy import delete, func, select, update
 from sqlalchemy.orm import Session
 
 from ..models.system_message import SystemMessage
@@ -86,6 +86,14 @@ def mark_messages_as_read(
     return result.rowcount or 0
 
 
+def delete_system_message(db: Session, message_id: str) -> bool:
+    """删除系统消息"""
+    stmt = delete(SystemMessage).where(SystemMessage.id == message_id)
+    result = db.execute(stmt)
+    db.commit()
+    return (result.rowcount or 0) > 0
+
+
 def get_unread_count(db: Session, user_id: str) -> int:
     """获取用户未读消息数量"""
     query = select(func.count()).select_from(SystemMessage).where(