fix: resolve all clippy warnings and convert integration_tests to custom cfg

- Add type aliases (FileRow, FolderRow, FolderRowPaginated, FolderRowOptUser) to reduce type complexity
- Simplify redundant closures in app_password_handler and webdav_handler
- Remove needless borrow in auth_handler
- Collapse nested if/let chains in login_lockout, webdav_lock, auth, rate_limit
- Box LockEntry in acquire() Err variant to fix large enum variant warning
- Rename DeviceCodeStatus::from_str to parse to avoid should_implement_trait lint
- Add #[allow(clippy::too_many_arguments)] and #[allow(clippy::result_unit_err)] where appropriate
- Convert integration_tests from cargo feature to custom cfg attribute
- Add check-cfg lint config in Cargo.toml for integration_tests cfg

src/domain/repositories/folder_repository.rs

@@ -8,7 +8,6 @@
 //! Concrete implementations (filesystem, PostgreSQL, S3, etc.) live in
 //! the infrastructure layer.
 
-
 use crate::common::errors::DomainError;
 use crate::domain::entities::folder::Folder;
 use crate::domain::services::path_service::StoragePath;