feat:credit_inquiries 테이블에 tenant_id 컬럼 추가

- 신용평가 조회회수 집계 기능을 위한 테넌트 구분 컬럼
- tenant_id, (tenant_id, inquired_at) 인덱스 추가

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

database/migrations/2026_01_28_163000_add_tenant_id_to_credit_inquiries_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::table('credit_inquiries', function (Blueprint $table) {
+            $table->unsignedBigInteger('tenant_id')->nullable()->after('id');
+            $table->index('tenant_id');
+            $table->index(['tenant_id', 'inquired_at']);
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::table('credit_inquiries', function (Blueprint $table) {
+            $table->dropIndex(['tenant_id', 'inquired_at']);
+            $table->dropIndex(['tenant_id']);
+            $table->dropColumn('tenant_id');
+        });
+    }
+};