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-cart.php

@@ -13,6 +13,7 @@ class WC_TPP_Cart {
         add_action('woocommerce_before_calculate_totals', array($this, 'apply_tier_package_pricing'), 10, 1);
         add_filter('woocommerce_cart_item_price', array($this, 'display_cart_item_price'), 10, 3);
         add_filter('woocommerce_cart_item_subtotal', array($this, 'display_cart_item_subtotal'), 10, 3);
+        add_filter('woocommerce_add_to_cart_validation', array($this, 'validate_package_quantity'), 10, 3);
     }
 
     public function apply_tier_package_pricing($cart) {
@@ -89,6 +90,53 @@ class WC_TPP_Cart {
         }
         return $subtotal;
     }
+
+    public function validate_package_quantity($passed, $product_id, $quantity) {
+        // Check if restriction is enabled globally or for this product
+        $global_restrict = get_option('wc_tpp_restrict_package_quantities', 'no') === 'yes';
+        $product_restrict = get_post_meta($product_id, '_wc_tpp_restrict_to_packages', true) === 'yes';
+
+        if (!$global_restrict && !$product_restrict) {
+            return $passed;
+        }
+
+        // Get packages for this product
+        $packages = get_post_meta($product_id, '_wc_tpp_packages', true);
+
+        if (empty($packages) || !is_array($packages)) {
+            return $passed;
+        }
+
+        // Check if the quantity matches any package
+        $valid_quantity = false;
+        $available_quantities = array();
+
+        foreach ($packages as $package) {
+            $available_quantities[] = $package['qty'];
+            if ($quantity == $package['qty']) {
+                $valid_quantity = true;
+                break;
+            }
+        }
+
+        if (!$valid_quantity) {
+            $product = wc_get_product($product_id);
+            $product_name = $product ? $product->get_name() : __('this product', 'wc-tier-package-prices');
+
+            wc_add_notice(
+                sprintf(
+                    __('The quantity %1$d is not available for %2$s. Please choose from the available package sizes: %3$s', 'wc-tier-package-prices'),
+                    $quantity,
+                    $product_name,
+                    implode(', ', $available_quantities)
+                ),
+                'error'
+            );
+            return false;
+        }
+
+        return $passed;
+    }
 }
 
 new WC_TPP_Cart();