Release version 1.1.0 - Package quantity restriction feature

Added comprehensive package quantity restriction functionality that allows
limiting product purchases to predefined package sizes only.

Features:
- Global setting to enable package quantity restrictions
- Per-product override for quantity restrictions
- Automatic hiding of quantity input field when restricted
- Frontend validation with package selection UI
- Server-side cart validation
- User-friendly error messages
- Complete translations for all supported languages

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

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

includes/class-wc-tpp-settings.php

@@ -104,6 +104,15 @@ class WC_TPP_Settings extends WC_Settings_Page {
                     ),
                 ),
 
+                array(
+                    'title'    => __('Restrict to Package Quantities', 'wc-tier-package-prices'),
+                    'desc'     => __('Limit quantities to defined package sizes only', 'wc-tier-package-prices'),
+                    'id'       => 'wc_tpp_restrict_package_quantities',
+                    'default'  => 'no',
+                    'type'     => 'checkbox',
+                    'desc_tip' => __('When enabled, customers can only purchase products in the exact quantities defined in packages. The quantity input field will be hidden and replaced with package selection buttons.', 'wc-tier-package-prices'),
+                ),
+
                 array(
                     'type' => 'sectionend',
                     'id'   => 'wc_tpp_settings',