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

admin/functions.php

@@ -122,15 +122,21 @@ function get_global_currency_array() {
     if(false === $ifSingleCurrency){
         // $currency_sort = [];
         $default_sort_key = null;
+        // Extract currency code from default_currency for comparison (handles case where default has symbol but multicurrencies don't)
+        $default_currency_code = explode(':::', $default_currency)[0];
         foreach($global_currencies as $key => $currency){
             $currency_value = $currency['currency'];
-            if($currency_value === $default_currency){
+            // Compare by currency code only (before first :::)
+            $currency_code = explode(':::', $currency_value)[0];
+            if($currency_code === $default_currency_code){
                 $default_sort_key = $key;
             }
         }
         $currency_sort = [$default_sort_key => $global_currencies[$default_sort_key]];
         unset($global_currencies[$default_sort_key]);
         $global_currencies = $currency_sort + $global_currencies;
+        // Convert associative array to indexed array for JavaScript
+        $global_currencies = array_values($global_currencies);
     }else{
         if(false === boolval($multicurrency)){
             $global_currencies = [
@@ -176,6 +182,31 @@ function formipay_get_flag_by_currency($currency) {
 
 }
 
+/**
+ * Get all currency flags from flags.json
+ * Returns an array mapping currency codes to base64 flag images
+ * This is the single source of truth for currency flags - never duplicate this data
+ *
+ * @return array Array of currency code => flag image mapping
+ */
+function formipay_get_all_currency_flags() {
+    static $currency_flags = null;
+
+    if ($currency_flags !== null) {
+        return $currency_flags;
+    }
+
+    $json = file_get_contents(FORMIPAY_PATH . 'admin/assets/json/flags.json');
+    $flags = json_decode($json, true);
+
+    $currency_flags = [];
+    foreach ($flags as $item) {
+        $currency_flags[$item['code']] = $item['flag'];
+    }
+
+    return $currency_flags;
+}
+
 function formipay_price_format($num = 0, $post_id = 0){
 
     $decimal_digits = 2;
@@ -361,7 +392,15 @@ function formipay_get_order($order_id) {
                     case 'payment_gateway':
                         $label = esc_html__( 'Payment Gateway', 'formipay' );
                         break;
-                    
+
+                    case 'shipping_country':
+                        $label = esc_html__( 'Shipping Country', 'formipay' );
+                        break;
+
+                    case 'shipping_method':
+                        $label = esc_html__( 'Shipping Method', 'formipay' );
+                        break;
+
                     default:
                         if(!empty($all_fields[$name.'_config'])){
                             $label = $all_fields[$name.'_config']['label'];