feat: migrate shipping to form-level and integrate flags.json as single source of truth

Shipping Migration:
- Move shipping configuration from product-level to form-level
- Add form shipping tab in form settings (no_shipping, flat_rate, free_shipping)
- Update FlatRate to register at form level instead of product level
- Update checkout logic to read from form settings
- Support percentage-based flat rate calculation
- Simplify shipping method IDs (flat_rate, free_shipping)

Currency Flags Integration:
- Add formipay_get_all_currency_flags() to read from admin/assets/json/flags.json
- Remove hardcoded CURRENCY_FLAGS emoji map from VariationField.js
- Create CurrencyFlag component to render base64 flag images
- Localize currency_flags to window.formipayProductDetails
- Update shipping info display in admin order details

Benefits:
- Form-level shipping prevents multiplying shipping costs per product
- Single source of truth for currency flags (flags.json)
- Better support for future cart system
- Consistent with e-commerce standards

includes/Render.php

@@ -653,6 +653,7 @@ class Render {
         wp_enqueue_script( 'choices', FORMIPAY_URL . 'vendor/ChoicesJS/choices.min.js', [], FORMIPAY_VERSION, true );
         wp_enqueue_script( 'formipay-popup', FORMIPAY_URL . 'public/assets/js/popup-action.js', ['jquery', 'choices'], FORMIPAY_VERSION, true);
         wp_enqueue_script( 'formipay-form', FORMIPAY_URL . 'public/assets/js/form-action.js', ['jquery', 'choices'], FORMIPAY_VERSION, true);
+        wp_enqueue_script( 'formipay-checkout-shipping', FORMIPAY_URL . 'public/assets/js/checkout-shipping.js', ['jquery', 'formipay-form'], FORMIPAY_VERSION, true);
         // Localize data for all forms
         $form_data = [
             'ajax_url' => admin_url('admin-ajax.php'),
@@ -661,6 +662,16 @@ class Render {
             'forms' => $this->get_form_data()
         ];
         wp_localize_script('formipay-form', 'formipay_form', $form_data);
+
+        // Localize shipping labels for checkout
+        $shipping_data = [
+            'labels' => [
+                'country' => __('Shipping Country', 'formipay'),
+                'selectCountry' => __('Select your country', 'formipay'),
+                'shippingMethod' => __('Shipping Method', 'formipay'),
+            ]
+        ];
+        wp_localize_script('formipay-checkout-shipping', 'formipay_shipping', $shipping_data);
         
     }
 
@@ -766,6 +777,11 @@ class Render {
             $allowed_currency_pack = $this->resolve_allowed_currencies($post_id);
             $currency_code         = $allowed_currency_pack['default_code'];
             $currency_cfg          = $this->resolve_currency_config($currency_code);
+
+            // Get form shipping settings
+            $form_settings = get_post_meta($post_id, 'formipay_form_settings', true);
+            $shipping_enabled = $form_settings['shipping_enabled'] ?? 'no_shipping';
+
             $form_data[$post_id] = [
                 'form_id' => $post_id,
                 'currency' => formipay_post_currency($post_id),
@@ -789,13 +805,14 @@ class Render {
                 'button_text' => formipay_get_post_meta($post_id, 'button_text'),
                 'button_processing_text' => formipay_get_post_meta($post_id, 'button_processing_text'),
                 'isPopup' => formipay_isPopup($post_id),
-                'trigger_selector' => formipay_get_post_meta($post_id, 'popup_click_selector') ? 
-                    formipay_get_post_meta($post_id, 'popup_trigger_selector') : 
+                'trigger_selector' => formipay_get_post_meta($post_id, 'popup_click_selector') ?
+                    formipay_get_post_meta($post_id, 'popup_trigger_selector') :
                     '.formipay-open-popup-button',
                 'modal_selector' => '#formipay-popup-' . $post_id,
                 'static_products' => array_filter(array_map('absint', explode(',', (string) formipay_get_post_meta($post_id, 'static_products')))),
                 'static_items'    => json_decode((string) formipay_get_post_meta($post_id, 'static_items'), true) ?: [],
                 'currency_code'   => (function($c){ $p = explode(':::', (string)$c); return $p[0] ?? 'IDR'; })(formipay_post_currency($post_id)),
+                'shipping_enabled' => $shipping_enabled, // Form-level shipping setting
             ];
         }