- Add methods to find and clean up obsoleted packages older than a specified TTL (`find_obsoleted_packages_older_than_ttl` and `cleanup_obsoleted_packages_older_than_ttl`) in `libips`.
- Implement a new `CleanupObsoleted` command in `pkg6repo` to handle cleanup operations.
- Update workspace `Cargo.toml` files with unified attributes for better consistency.
- Adjust dependencies (`libips` version patterns, `thiserror` updates) and enhance metadata management for obsoleted packages.
- Enhance repository operations by adding batch processing and robust logging during cleanup.
- Introduce `#[serde(skip_serializing_if = "is_empty", default)]` for various optional fields to streamline serialization and ensure defaults are applied during deserialization.
- Add `tracing::debug` logging for enhanced error context in JSON deserialization fallback logic.
- Update tests to reflect changes in manifest parsing, including new cases for the updated JSON format.
