Initial implementation of WooCommerce Composable Products plugin

Implemented custom WooCommerce product type allowing customers to build their own
product bundles by selecting from predefined sets of products.

Features:
- Custom "Composable Product" type with admin interface
- Product selection by category, tag, or SKU
- Configurable selection limits (global and per-product)
- Dual pricing modes: fixed price or sum of selected products
- Modern responsive frontend with Twig templates
- AJAX add-to-cart functionality
- Full internationalization support (.pot file)
- WooCommerce settings integration
- Comprehensive documentation

Technical implementation:
- PHP 8.3+ with PSR-4 autoloading
- Twig 3.0 templating engine via Composer
- Vanilla JavaScript with jQuery for frontend interactions
- WordPress and WooCommerce hooks for seamless integration
- Security: input sanitization, validation, and output escaping
- Translation-ready with text domain 'wc-composable-product'

Documentation:
- README.md: Project overview and features
- INSTALL.md: Installation and usage guide
- IMPLEMENTATION.md: Technical architecture
- CHANGELOG.md: Version history

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

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

CHANGELOG.md

@@ -0,0 +1,34 @@
+# 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/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [1.0.0] - 2024-12-31
+
+### Added
+- Initial release
+- Composable product type for WooCommerce
+- Product selection by category, tag, or SKU
+- Configurable selection limits (global and per-product)
+- Two pricing modes: fixed price or sum of selected products
+- Admin settings page
+- Frontend product selector with grid layout
+- AJAX add-to-cart functionality
+- Twig template engine integration
+- Full internationalization support
+- Responsive design
+- WooCommerce cart integration
+- Product data validation
+
+### Features
+- Select products from predefined categories, tags, or SKUs
+- Limit number of items customers can select
+- Visual product selector with images and prices
+- Real-time price calculation
+- Clean, modern UI
+- Mobile responsive
+- Translation ready
+
+[1.0.0]: https://github.com/magdev/wc-composable-product/releases/tag/v1.0.0