Fix Phase_66_004 migration — columns already exist from Phase_52_004

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

database/migrations/Phase_66_004_add_medical_board_fields.php

@@ -4,9 +4,6 @@ declare(strict_types=1);
 use App\Core\Database;
 
 return function (Database $db): void {
-    $db->raw("
-        ALTER TABLE player_medical_records
-        ADD COLUMN approved_by BIGINT UNSIGNED NULL,
-        ADD COLUMN approved_at DATETIME NULL
-    ");
+    // approved_by and approved_at already exist from Phase_52_004
+    // This migration is retained as a no-op to keep the sequence consistent
 };