- Implemented `executors` module for applying manifests with support for directories, files, and links.
- Added `action_plan` module to merge and execute install plans from manifests.
- Introduced `run_sample_install.sh` script for testing installations, including dry-run and real execution.
- Enhanced `pkg6` install logic to resolve and apply action plans.
- Improved manifest management with `save_manifest` and repository-based fetching.
- Add `ProgressReporter` trait with `start`, `update`, and `finish` methods for customizable progress tracking during operations.
- Implement `ProgressInfo` struct for detailed progress state reporting, including operation, progress, and context information.
- Create a no-op implementation `NoopProgressReporter` for cases where progress reporting is not needed.
- Enhance `pkg6` with structured error handling using `Pkg6Error` and new diagnostic variants for I/O, JSON, FMRI, and logging errors.
- Update `Image` functionality to leverage progress reporting during catalog downloads and include robust publisher management.
- Introduce `TestProgressReporter` for unit tests to validate progress reporting integration.
