Major improvements: Fix download limits, enhance license display, fix software filenames

🔧 Bug Fixes:
- Fixed download limits defaulting to 5 instead of 0 for unlimited downloads
- Fixed software license filename sanitization (spaces→dashes, dots→underscores, proper .zip extension)
- Software downloads now show as "Test-Plugin-v2-2-0.zip" instead of "Test Plugin v2.2.0"

✨ UI/UX Enhancements:
- Redesigned license key display to span full table width with FontAwesome copy icons
- Added responsive CSS styling for license key rows
- Integrated FontAwesome CDN for modern copy icons

🏗️ Architecture Improvements:
- Added comprehensive filename sanitization in both download handler and API paths
- Enhanced software license product handling for local package files
- Improved error handling and logging throughout download processes

📦 Infrastructure:
- Added Gitea workflows for automated releases on push to main
- Created comprehensive .gitignore excluding test files and browser automation
- Updated documentation with all recent improvements and technical insights

🔍 Technical Details:
- Software license products served from wp-content/uploads/wpdd-packages/
- Download flow: token → process_download_by_token() → process_download() → deliver_file()
- Dual path coverage for both API downloads and regular file delivery
- Version placeholder system for automated deployment

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

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

includes/class-wpdd-metaboxes.php

@@ -316,7 +316,7 @@ class WPDD_Metaboxes {
                         <?php _e('Download Limit', 'wp-digital-download'); ?>
                     </label>
                     <input type="number" id="wpdd_download_limit" name="wpdd_download_limit" 
-                           value="<?php echo esc_attr($download_limit ?: 5); ?>" min="0" />
+                           value="<?php echo esc_attr($download_limit ?: 0); ?>" min="0" />
                     <span class="description">
                         <?php _e('Number of times a customer can download after purchase. 0 = unlimited', 'wp-digital-download'); ?>
                     </span>