feat: implement comprehensive release process and automation (issue #81)

- Add complete release automation script (release.py) with version management
- Add semantic versioning validation and git integration
- Create automated changelog generation from git commits
- Add comprehensive Makefile targets for release workflow
- Set up package building with source and wheel distributions
- Add git tagging and repository management
- Create extensive release documentation (RELEASE.md)
- Add CHANGELOG.md with standardized format
- Update dependencies in pyproject.toml (add toml package)

Release commands added:
- make release-status - Show current release status
- make release-validate - Validate repository for release
- make release-prepare VERSION=x.y.z - Prepare new release
- make release-build - Build release packages
- make release-publish VERSION=x.y.z - Complete release workflow
- make release-dry-run VERSION=x.y.z - Test release preparation

Features:
- Semantic versioning with pre-release support
- Automated version updates across files
- Git status validation and branch checking
- Test execution validation
- Package building with build tool integration
- Git tagging with proper annotations
- Comprehensive error handling and validation

Resolves #81

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

pyproject.toml

@@ -8,7 +8,7 @@ version = "0.1.0"
 description = "Advanced Markdown engine for structured content"
 readme = "README.md"
 requires-python = ">=3.8"
-dependencies = ["markdown-it-py", "PyYAML", "click>=8.0.0", "tabulate>=0.9.0", "jsonpath-ng>=1.5.0", "aiohttp>=3.8.0"]
+dependencies = ["markdown-it-py", "PyYAML", "click>=8.0.0", "tabulate>=0.9.0", "jsonpath-ng>=1.5.0", "aiohttp>=3.8.0", "toml"]
 
 [project.scripts]
 markitect = "markitect.cli:main"