fix(data): archive separated child from membership 1701

Retroactive fix for child that was separated but not archived from the
parent's family tree due to the old code not setting is_archived=1.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

database/migrations/Phase_98_008_archive_separated_children_1701.php

+<?php
+declare(strict_types=1);
+
+return static function (\App\Core\Database $db): void {
+    // Archive separated children under membership number 1701
+    // These children were separated (فصل) but the old code didn't set is_archived=1
+    $db->query(
+        "UPDATE children c
+         JOIN members m ON m.id = c.member_id
+         SET c.is_archived = 1,
+             c.archived_at = NOW(),
+             c.updated_at = NOW()
+         WHERE m.membership_number = '1701'
+           AND c.status = 'separated'
+           AND c.is_archived = 0"
+    );
+};