fix(seasonal): skip 505 EGP form fee for seasonal memberships

Seasonal members don't need the استمارة fee. Set form_fee_paid=true
in getSeasonalBill() so the member show page skips the form fee
step entirely and goes straight to seasonal fee payment.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/Modules/Members/Services/BillingService.php

@@ -138,8 +138,8 @@ final class BillingService
         $db = App::getInstance()->db();
         $items = [];
 
-        $formFeeData = self::getFormFeeItem($db, $memberId);
-        $items[] = $formFeeData['item'];
+        // Seasonal members skip the 505 EGP form fee
+        $formFeeData = ['paid' => true, 'pending' => false, 'item' => null];
 
         $seasonalRecord = $db->selectOne(
             "SELECT * FROM seasonal_memberships WHERE member_id = ? AND person_type = 'member' AND is_archived = 0 ORDER BY id DESC LIMIT 1",