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>

README.md

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+# WooCommerce Composable Products
+
+Create composable products where customers can select a limited number of items from a configurable set of products.
+
+## Description
+
+This plugin adds a new product type to WooCommerce that allows customers to build their own product bundles by selecting from a predefined set of simple or variable products. Think of it as a "build your own gift box" or "create your sticker pack" feature.
+
+### Key Features
+
+- **Custom Product Type**: New "Composable Product" type in WooCommerce
+- **Flexible Selection**: Define available products by category, tag, or SKU
+- **Configurable Limits**: Set global or per-product selection limits
+- **Pricing Options**: Fixed price or sum of selected products
+- **Multi-language Support**: Fully translatable with i18n support
+- **Modern UI**: Clean interface built with Twig templates and vanilla JavaScript
+
+## Requirements
+
+- PHP 8.3 or higher
+- WordPress 6.0 or higher
+- WooCommerce 8.0 or higher
+
+## Installation
+
+1. Upload the plugin files to `/wp-content/plugins/wc-composable-product/`
+2. Run `composer install --no-dev` in the plugin directory
+3. Activate the plugin through the 'Plugins' menu in WordPress
+4. Configure global settings under WooCommerce > Settings > Composable Products
+
+## Usage
+
+### Creating a Composable Product
+
+1. Go to Products > Add New
+2. Select "Composable Product" as the product type
+3. Configure product details:
+   - Set the selection limit (or use global default)
+   - Choose pricing mode (fixed or sum)
+   - Define available products by category, tag, or SKU
+4. Publish the product
+
+### Global Settings
+
+Navigate to WooCommerce > Settings > Composable Products to configure:
+- Default selection limit
+- Default pricing mode
+- Display options
+
+## Development
+
+This project was created with AI assistance (Claude.AI) and follows WordPress and WooCommerce best practices.
+
+### Building from Source
+
+```bash
+composer install
+```
+
+### Translation
+
+Generate POT file:
+```bash
+wp i18n make-pot . languages/wc-composable-product.pot
+```
+
+## License
+
+GPL v3 or later - see LICENSE file for details
+
+## Author
+
+Marco Graetsch
+
+## Support
+
+For issues and feature requests, please use the GitHub issue tracker.