Add configuration options for backup

**Description**
Currently lib lacks proper filtering support.

**Proposed solution**
Add configurable filtering with sensible defaults.

**Priority**: Low/Medium

Start by locating the backup implementation and configuration handling under lib, then inspect how existing options are defined and applied. Determine the filtering scope and sensible defaults from the surrounding code before making changes. Done means backup filtering is configurable and defaults behave safely; add or update tests if the project has coverage for this area.

Written by the indexing model from the issue text.