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/interfaces/api/handlers/auth_handler.rs

@@ -150,7 +150,7 @@ async fn login(
         );
         return Err(AppError::new(
             StatusCode::TOO_MANY_REQUESTS,
-            &format!(
+            format!(
                 "Account temporarily locked due to too many failed attempts. Try again in {} seconds.",
                 lockout_secs
             ),