Add professional project structure and documentation

New files:
- LICENSE (MIT) - Required legal file
- CHANGELOG.md - Version history following Keep a Changelog
- CONTRIBUTING.md - Contributor guidelines
- CODE_OF_CONDUCT.md - Community standards
- .github/ISSUE_TEMPLATE/ - Bug report and feature request forms
- .github/PULL_REQUEST_TEMPLATE.md - PR checklist
- src/stegasoo/py.typed - PEP 561 type hint marker
- examples/ - Usage examples (basic, file embedding, channel keys)

Updated:
- README.md - Added CI status badges

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

README.md

@@ -2,8 +2,10 @@
 
 A secure steganography system for hiding encrypted messages in images using hybrid authentication.
 
+[![Tests](https://github.com/adlee-was-taken/stegasoo/actions/workflows/test.yml/badge.svg)](https://github.com/adlee-was-taken/stegasoo/actions/workflows/test.yml)
+[![Lint](https://github.com/adlee-was-taken/stegasoo/actions/workflows/lint.yml/badge.svg)](https://github.com/adlee-was-taken/stegasoo/actions/workflows/lint.yml)
 ![Python](https://img.shields.io/badge/Python-3.10--3.12-blue)
-![License](https://img.shields.io/badge/License-MIT-green)
+[![License: MIT](https://img.shields.io/badge/License-MIT-green.svg)](https://opensource.org/licenses/MIT)
 ![Security](https://img.shields.io/badge/Security-AES--256--GCM-red)
 ![Version](https://img.shields.io/badge/Version-4.0.1-purple)