feat: Add automated changelog generation

[danbaruka]

Description

This PR adds automated changelog generation using standard-version to automatically generate changelogs from conventional commit messages.

What problem does this PR solve?

• Manual changelog maintenance is time-consuming and error-prone
• Inconsistent changelog formatting across releases
• Difficulty tracking changes between specific date ranges for reporting

What is the purpose of this change?

• Automatically generate changelogs from conventional commits
• Provide simple workflow for version releases with automatic version bumping
• Enable generating changelogs for specific date ranges (e.g., Q1 reports)
• Ensure changelog consistency following Keep a Changelog format

Related Issue

Fixes #78

Type of Change

• New feature (non-breaking change that adds functionality)
• Bug fix (non-breaking change that fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactor (improves code structure or readability without changing functionality)
• Other (please describe):

Changes Made

New Files:

• .github/workflows/changelog.yml - GitHub Action to verify changelog on tag push
• .versionrc.json - Configuration for standard-version
• scripts/changelog-dates.js - Script to generate changelog between two dates
• package.json (root) - Added standard-version dependency and release scripts

Modified Files:

• CHANGELOG.md - Fixed formatting issues and updated to Keep a Changelog format

New npm Scripts:

• npm run release - Generate changelog, bump version, create tag
• npm run release:minor/major/patch - Version bump options
• npm run changelog:dates - Generate changelog for date range

Checklist

• My code follows the project's coding style and guidelines.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have updated the documentation (if applicable).
• My changes generate no new warnings or errors.
• I have added tests that prove my fix is effective or that my feature works. (N/A - Infrastructure setup)
• I have checked for merge conflicts.
• I have rebased my branch onto the latest main or master branch.