Introduce CHANGELOG.md file

## Description
We need to introduce a CHANGELOG.md file to track changes between versions and provide users with clear information about updates, new features, and bug fixes.

## Problem
Without a proper changelog, it's difficult for users and contributors to understand what has changed between versions, which features have been added, and which bugs have been fixed.

## Proposed Solution
1. Create a CHANGELOG.md file in the root of the repository
2. Document changes for previous releases (if feasible)
3. Establish a process for updating the changelog with new releases

## Implementation Details
- Use the [Keep a Changelog](https://keepachangelog.com/en/1.0.0/) format
- Include sections for Added, Changed, Deprecated, Removed, Fixed, and Security
- Link to GitHub issues and pull requests where appropriate
- Maintain the changelog for all future releases

## Acceptance Criteria
- CHANGELOG.md file exists in the repository root
- Format is clear, consistent, and follows established practices
- Recent changes are documented with appropriate details
- Process is in place for maintaining the changelog with future releases

Create CHANGELOG.md in the repository root and review the repository history to identify recent changes worth documenting. Use the Keep a Changelog sections named in the issue, link relevant issues or pull requests where available, and document how future releases should update the file. Done means the file exists, recent changes are covered, and the format is consistent.

Written by the indexing model from the issue text.