feat:법인카드 선불결제 테이블 마이그레이션 추가

corporate_card_prepayments 테이블 생성 (tenant_id, year_month, amount, memo)

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

database/migrations/2026_02_11_100000_create_corporate_card_prepayments_table.php

@@ -0,0 +1,26 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Schema::create('corporate_card_prepayments', function (Blueprint $table) {
+            $table->id();
+            $table->unsignedBigInteger('tenant_id');
+            $table->string('year_month', 7); // "2026-02"
+            $table->decimal('amount', 15, 0)->default(0);
+            $table->string('memo', 200)->nullable();
+            $table->timestamps();
+            $table->unique(['tenant_id', 'year_month']);
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::dropIfExists('corporate_card_prepayments');
+    }
+};