feat:barobill_members 테이블에 server_mode 컬럼 추가

회원사별로 바로빌 테스트/운영 서버를 개별 설정할 수 있도록 컬럼 추가
- server_mode: enum('test', 'production'), 기본값 'test'

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

database/migrations/2026_02_03_100000_add_server_mode_to_barobill_members_table.php

@@ -0,0 +1,31 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::table('barobill_members', function (Blueprint $table) {
+            $table->enum('server_mode', ['test', 'production'])
+                  ->default('test')
+                  ->after('status')
+                  ->comment('바로빌 서버 모드 (test: 테스트서버, production: 운영서버)');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('barobill_members', function (Blueprint $table) {
+            $table->dropColumn('server_mode');
+        });
+    }
+};