Initialize composer project for WooCommerce Licensed Product Client

- Set up composer.json with package metadata and PSR-4 autoloading
- Add symfony/http-client ^7.0 as HTTP client dependency
- Create project structure (src/, tests/, tmp/)
- Add README.md with project overview
- Add CHANGELOG.md to track version history
- Add .gitignore for vendor and cache files
- Include OpenAPI specification in tmp/openapi.json

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

CHANGELOG.md

@@ -0,0 +1,18 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+## [0.0.1] - 2026-01-22
+
+### Added
+
+- Initial composer project setup
+- Package configuration with PSR-4 autoloading
+- Symfony HttpClient dependency (^7.0)
+- Project documentation (README.md, CHANGELOG.md)
+- OpenAPI specification reference in tmp/openapi.json