feat: Add flags to Country select + Bank account repeater for BACS

1. Added Emoji Flags to Country/Region Select ✅

   Before: Indonesia
   After:  🇮🇩 Indonesia

   Implementation:
   - Uses same countryCodeToEmoji() helper
   - Flags for all countries in dropdown
   - Better visual identification

2. Implemented Bank Account Repeater Field ✅

   New field type: 'account'
   - Add/remove multiple bank accounts
   - Each account has 6 fields:
     * Account Name (required)
     * Account Number (required)
     * Bank Name (required)
     * Sort Code / Branch Code (optional)
     * IBAN (optional)
     * BIC / SWIFT (optional)

   UI Features:
   ✅ Compact card layout with muted background
   ✅ 2-column grid on desktop, 1-column on mobile
   ✅ Delete button per account (trash icon)
   ✅ Add button at bottom with plus icon
   ✅ Account numbering (Account 1, Account 2, etc.)
   ✅ Smaller inputs (h-9) for compact layout
   ✅ Clear labels with required indicators

   Perfect for:
   - Direct Bank Transfer (BACS)
   - Manual payment methods
   - Multiple bank account management

3. Updated GenericGatewayForm ✅

   Added support:
   - New 'account' field type
   - BankAccount interface
   - Repeater logic (add/remove/update)
   - Plus and Trash2 icons from lucide-react

   Data structure:
   interface BankAccount {
     account_name: string;
     account_number: string;
     bank_name: string;
     sort_code?: string;
     iban?: string;
     bic?: string;
   }

Benefits:
✅ Country select now has visual flags
✅ Bank accounts are easy to manage
✅ Compact, responsive UI
✅ Clear visual hierarchy
✅ Supports international formats (IBAN, BIC, Sort Code)

Files Modified:
- Store.tsx: Added flags to country select
- GenericGatewayForm.tsx: Bank account repeater
- SubmenuBar.tsx: Fullscreen prop (user change)

admin-spa/src/routes/Settings/Store.tsx

@@ -249,11 +249,14 @@ export default function StoreDetailsPage() {
           <SearchableSelect
             value={settings.country}
             onChange={(v) => updateSetting('country', v)}
-            options={countries.map((country: { code: string; name: string }) => ({
-              value: country.code,
-              label: country.name,
-              searchText: country.name,
-            }))}
+            options={countries.map((country: { code: string; name: string }) => {
+              const flagEmoji = countryCodeToEmoji(country.code);
+              return {
+                value: country.code,
+                label: `${flagEmoji} ${country.name}`.trim(),
+                searchText: `${country.code} ${country.name}`,
+              };
+            })}
             placeholder="Select country..."
           />
         </SettingsSection>