feat: add automated release notes synchronization from GitHub releases

[Copilot]

Addresses issue #[issue_number] by implementing a comprehensive solution to automatically sync the local CHANGELOG.md file with GitHub release notes, ensuring documentation stays current without manual intervention.

Problem

The local CHANGELOG.md file contained minimal, hardcoded release notes that quickly became outdated compared to the rich, detailed release notes published in GitHub releases. This created inconsistency between local documentation and published releases.

Solution

This PR introduces both automated and manual synchronization capabilities:

🤖 Automated GitHub Workflow

• File: .github/workflows/sync-release-notes.yml
• Triggers: Automatically runs when releases are published or edited
• Manual trigger: Can be executed on-demand via GitHub Actions
• Security: Uses hardened runner and secure token handling
• Smart commits: Only commits when changes are detected

🛠️ Local Sync Script

• File: scripts/sync-changelog.js
• Usage: npm run sync-changelog for live sync, npm run sync-changelog:test for testing
• Authentication: Supports both GitHub CLI and API token methods
• Fallback: Graceful degradation when authentication isn't available

🧠 Intelligent Processing

The script intelligently processes release data:

• Preserves existing [Unreleased] section structure
• Converts release notes to proper changelog bullet format
• Distinguishes between pre-releases and regular releases
• Removes GitHub-specific content (Full Changelog links)
• Maintains chronological order (newest first)

📖 Enhanced Documentation

Updated README.md with comprehensive usage instructions including:

• Manual sync commands
• Automatic sync behavior explanation
• Test mode usage
• Authentication requirements

Example Transformation

Before:

## [0.0.1] - Initial Release
- Initial release
- Real-time token tracking with status bar display

After:

## [0.0.1] - Pre-release
- First rough version, not complete of course!
- Only tested on windows
- Use at your own risk 😄
- Screenshots in the README
- VS Code v1.104 or higher

Usage

• Automatic: Workflow runs automatically on release events
• Manual: npm run sync-changelog to sync anytime
• Testing: npm run sync-changelog:test to test with sample data

This ensures the local changelog never lags behind GitHub releases, providing users with consistent and up-to-date release information across all documentation sources.

Original prompt

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This section details on the original issue you should resolve

<issue_title>[FEATURE] Extension release notes from GitHub Release Notes</issue_title>
<issue_description>Is your feature request related to a problem? Please describe.
The release notes in the hardcoded file always are lagging with the release notes from the GitHub release we generate. Setup a process to automatically update the release notes in the local file

Describe the solution you'd like
Easy and automated!

Priority
How important is this feature to you?

• Critical - I can't use the extension effectively without this
• High - This would significantly improve my experience
• Medium - This would be a nice addition
• Low - This is just a suggestion
  </issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #27

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