feat: 实现清理失效账号安全方案（包含预览、SSE测试、安全删除以及本地标记清空）

backend/app/schemas/website.py

@@ -243,3 +243,28 @@ class OrganizeGroupsResponse(BaseModel):
     success: bool
     message: str
     items: list[OrganizeGroupsItem]
+
+
+class CleanupInvalidAccountsItem(BaseModel):
+    account_id: str
+    account_name: Optional[str] = None
+    upstream_key_id: Optional[int] = None
+    upstream_name: Optional[str] = None
+    source_group_name: Optional[str] = None
+    reason: str
+    test_status: str
+    cleanup_allowed: bool
+    action_status: Optional[str] = None
+    message: str = ""
+
+
+class CleanupInvalidAccountsPreviewResponse(BaseModel):
+    success: bool
+    message: str
+    items: list[CleanupInvalidAccountsItem]
+
+
+class CleanupInvalidAccountsExecuteResponse(BaseModel):
+    success: bool
+    message: str
+    items: list[CleanupInvalidAccountsItem]