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-product-meta.php

@@ -69,6 +69,15 @@ class WC_TPP_Product_Meta {
             <p class="form-field">
                 <button type="button" class="button wc-tpp-add-package"><?php _e('Add Package', 'wc-tier-package-prices'); ?></button>
             </p>
+
+            <?php
+            woocommerce_wp_checkbox(array(
+                'id'          => '_wc_tpp_restrict_to_packages',
+                'label'       => __('Restrict to Package Quantities', 'wc-tier-package-prices'),
+                'description' => __('Only allow quantities defined in packages above', 'wc-tier-package-prices'),
+                'desc_tip'    => true,
+            ));
+            ?>
         </div>
 
         <script type="text/html" id="wc-tpp-tier-row-template">
@@ -151,6 +160,10 @@ class WC_TPP_Product_Meta {
         } else {
             delete_post_meta($post_id, '_wc_tpp_packages');
         }
+
+        // Save package quantity restriction setting
+        $restrict_to_packages = isset($_POST['_wc_tpp_restrict_to_packages']) ? 'yes' : 'no';
+        update_post_meta($post_id, '_wc_tpp_restrict_to_packages', $restrict_to_packages);
     }
 }