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>

INSTALL.md

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+# Installation Guide
+
+## Requirements
+
+Before installing the WooCommerce Composable Products plugin, ensure your system meets these requirements:
+
+- **PHP**: 8.3 or higher
+- **WordPress**: 6.0 or higher
+- **WooCommerce**: 8.0 or higher
+- **Composer**: For dependency management
+
+## Installation Steps
+
+### 1. Upload Plugin Files
+
+Upload the plugin directory to your WordPress installation:
+
+```bash
+/wp-content/plugins/wc-composable-product/
+```
+
+### 2. Install Dependencies
+
+Navigate to the plugin directory and install dependencies:
+
+```bash
+cd /wp-content/plugins/wc-composable-product/
+composer install --no-dev --optimize-autoloader
+```
+
+### 3. Activate Plugin
+
+1. Log in to your WordPress admin panel
+2. Navigate to **Plugins > Installed Plugins**
+3. Find "WooCommerce Composable Products"
+4. Click **Activate**
+
+### 4. Configure Settings
+
+After activation, configure the plugin:
+
+1. Navigate to **WooCommerce > Settings**
+2. Click on the **Composable Products** tab
+3. Configure default settings:
+   - **Default Selection Limit**: Number of items customers can select (default: 5)
+   - **Default Pricing Mode**: Choose between "Sum of selected products" or "Fixed price"
+   - **Display Options**: Toggle product images, prices, and totals
+
+## Creating Your First Composable Product
+
+### Step 1: Create a New Product
+
+1. Go to **Products > Add New**
+2. Enter a product name (e.g., "Custom Sticker Pack")
+
+### Step 2: Set Product Type
+
+1. In the **Product Data** panel, select **Composable product** from the dropdown
+
+### Step 3: Configure General Settings
+
+In the **General** tab:
+- Set a **Regular price** (used if pricing mode is "Fixed")
+- Configure **Selection Limit** (leave empty to use global default)
+- Choose **Pricing Mode** (leave empty to use global default)
+
+### Step 4: Configure Composable Options
+
+Click on the **Composable Options** tab:
+
+1. **Selection Criteria**: Choose how to select available products
+   - **By Category**: Select product categories
+   - **By Tag**: Select product tags
+   - **By SKU**: Enter comma-separated SKUs
+
+2. Based on your selection:
+   - **Categories**: Select one or more categories from the dropdown
+   - **Tags**: Select one or more tags from the dropdown
+   - **SKUs**: Enter SKUs like: `STICKER-01, STICKER-02, STICKER-03`
+
+### Step 5: Publish
+
+Click **Publish** to make your composable product live.
+
+## Frontend Usage
+
+When customers visit your composable product:
+
+1. They see a grid of available products based on your criteria
+2. They can select up to the configured limit
+3. The total price updates in real-time (if using sum pricing mode)
+4. Click "Add to Cart" to add the composition to their cart
+5. Selected products are displayed in the cart
+
+## Troubleshooting
+
+### Plugin Won't Activate
+
+- Ensure WooCommerce is installed and activated first
+- Check PHP version (must be 8.3+)
+- Verify Composer dependencies are installed
+
+### Products Not Showing in Selector
+
+- Check that products are published and in stock
+- Verify the selection criteria (category/tag/SKU) is correct
+- Ensure products match the criteria you configured
+
+### Twig Template Errors
+
+- Ensure the `vendor/` directory exists and contains Twig
+- Run `composer install` again
+- Check that the `cache/` directory is writable
+
+### JavaScript Not Working
+
+- Clear browser cache
+- Check browser console for errors
+- Ensure jQuery is loaded (WooCommerce includes it)
+
+## Updating
+
+When updating the plugin:
+
+1. Deactivate the plugin
+2. Replace plugin files
+3. Run `composer install --no-dev --optimize-autoloader`
+4. Reactivate the plugin
+5. Clear all caches (WordPress, browser, CDN)
+
+## Uninstallation
+
+To completely remove the plugin:
+
+1. Deactivate the plugin
+2. Delete the plugin from the Plugins page
+3. Optionally clean up database entries (WooCommerce will handle this automatically)
+
+## Support
+
+For issues and feature requests:
+- GitHub: https://github.com/magdev/wc-composable-product/issues
+- Documentation: See README.md
+
+## Next Steps
+
+- Customize the template by editing `templates/product-selector.twig`
+- Modify styles in `assets/css/frontend.css`
+- Translate the plugin using the provided `.pot` file
+- Create categories/tags for easier product organization