feat: [approvals] 사용인감계 양식 데이터 마이그레이션 추가

- 모든 테넌트에 seal_usage 양식 자동 등록

database/migrations/2026_03_06_210000_add_seal_usage_form.php

@@ -0,0 +1,38 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Support\Facades\DB;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        $tenants = DB::table('tenants')->whereNull('deleted_at')->pluck('id');
+
+        foreach ($tenants as $tenantId) {
+            $exists = DB::table('approval_forms')
+                ->where('tenant_id', $tenantId)
+                ->where('code', 'seal_usage')
+                ->exists();
+
+            if (! $exists) {
+                DB::table('approval_forms')->insert([
+                    'tenant_id' => $tenantId,
+                    'name' => '사용인감계',
+                    'code' => 'seal_usage',
+                    'category' => 'certificate',
+                    'template' => '[]',
+                    'body_template' => '',
+                    'is_active' => true,
+                    'created_at' => now(),
+                    'updated_at' => now(),
+                ]);
+            }
+        }
+    }
+
+    public function down(): void
+    {
+        DB::table('approval_forms')->where('code', 'seal_usage')->delete();
+    }
+};