fix(migration): skip form_number column that already exists; only add deceased_member_name

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

database/migrations/Phase_98_004_add_death_transfer_fields_to_members.php

 <?php
 declare(strict_types=1);
 
-return [
-    'up' => "
-ALTER TABLE members ADD COLUMN form_number VARCHAR(50) NULL AFTER original_membership_number;
-ALTER TABLE members ADD COLUMN deceased_member_name VARCHAR(255) NULL AFTER form_number
-",
-    'down' => "
-ALTER TABLE members DROP COLUMN IF EXISTS form_number;
-ALTER TABLE members DROP COLUMN IF EXISTS deceased_member_name
-",
-];
+return function (\App\Core\Database $db): void {
+    // form_number already exists — only add deceased_member_name if missing
+    $exists = $db->selectOne(
+        "SELECT 1 FROM information_schema.columns WHERE table_schema = DATABASE() AND table_name = 'members' AND column_name = 'deceased_member_name'"
+    );
+    if (!$exists) {
+        $db->raw("ALTER TABLE members ADD COLUMN deceased_member_name VARCHAR(255) NULL AFTER form_number");
+    }
+};