- Made `receive_one` public to allow external use.
- Improved signature payload fetching, storing, and fallback logic for `FileBackend` repositories.
- Added test case `test_receive_with_signature` to verify signature handling and repository storage.
- Extended manifest fields in transaction logic to support additional attributes (e.g., `users`, `groups`, `drivers`).
- Updated `RestBackend` to handle extended file path lookups for signature payloads.
- Implemented support for fetching, importing, and storing signature payloads during transaction creation.
- Added the `Signature` struct to represent signature-related action data.
- Updated `Manifest` to include and process `signatures` as part of its fields.
- Enabled signature file imports with proper path resolution in `pkg6repo`.
- Introduced `pkg6recv` for downloading packages from IPS repositories with support for recursive dependency fetching.
- Implemented CLI commands with `clap` for source/destination setup, package selection, and publisher defaults.
- Added `ConsoleProgressReporter` for detailed receive progress visibility.
- Enhanced the `Manifest` parser to support JSON format alongside IPS text format.
- Updated `FileBackend` and `RestBackend` repositories to fetch manifests and payloads in new operations.
- Extended `Digest` utilities for payload integrity checks.
- Added tests to verify basic functionality and manifest format preservation.
