Consider adding a changelog to track version history

## Feature Request

### Summary
A `CHANGELOG.md` file would help users understand what changed between versions and make upgrade decisions easier.

### Motivation
When upgrading dependencies, developers need to know:
- What bugs were fixed
- What new features were added
- Whether there are any breaking changes

### Suggested Format
Follow the [Keep a Changelog](https://keepachangelog.com) convention:

```markdown
# Changelog

## [Unreleased]

## [1.2.0] - 2024-01-15
### Added
- New feature X
### Fixed
- Bug with Y under Z conditions
### Changed
- Behaviour of Z is now more consistent
```

### Additional Context
This is purely a documentation change with no code impact.

Start by reviewing the repository's release and version history, along with existing documentation conventions. Add a CHANGELOG.md following the Keep a Changelog structure, documenting relevant past changes and an Unreleased section; completion means users can identify fixes, features, changes, and breaking changes between versions.

Written by the indexing model from the issue text.