feat: [approval] Phase 2 마이그레이션 추가

- approval_steps: parallel_group, acted_by, approval_type 컬럼 추가
- approvals: recall_reason, parent_doc_id 컬럼 추가
- approval_delegations 테이블 생성 (위임/대결)

database/migrations/2026_02_27_100003_add_phase2_columns_to_approval_steps_table.php

@@ -0,0 +1,27 @@
+<?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('approval_steps', function (Blueprint $table) {
+            $table->integer('parallel_group')->nullable()->after('step_type')
+                ->comment('병렬 그룹 번호');
+            $table->foreignId('acted_by')->nullable()->after('approver_id')
+                ->comment('실제 처리자 (대결)');
+            $table->string('approval_type', 20)->default('normal')->after('status')
+                ->comment('결재 유형: normal/pre_decided/delegated');
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::table('approval_steps', function (Blueprint $table) {
+            $table->dropColumn(['parallel_group', 'acted_by', 'approval_type']);
+        });
+    }
+};

database/migrations/2026_02_27_100004_add_phase2_columns_to_approvals_table.php

@@ -0,0 +1,25 @@
+<?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('approvals', function (Blueprint $table) {
+            $table->text('recall_reason')->nullable()->after('completed_at')
+                ->comment('회수 사유');
+            $table->foreignId('parent_doc_id')->nullable()->after('recall_reason')
+                ->comment('재기안 원본 문서');
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::table('approvals', function (Blueprint $table) {
+            $table->dropColumn(['recall_reason', 'parent_doc_id']);
+        });
+    }
+};

database/migrations/2026_02_27_100005_create_approval_delegations_table.php

@@ -0,0 +1,34 @@
+<?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('approval_delegations', function (Blueprint $table) {
+            $table->id();
+            $table->foreignId('tenant_id')->constrained()->onDelete('cascade');
+            $table->foreignId('delegator_id')->constrained('users')->comment('위임자');
+            $table->foreignId('delegate_id')->constrained('users')->comment('대리인');
+            $table->date('start_date')->comment('시작일');
+            $table->date('end_date')->comment('종료일');
+            $table->json('form_ids')->nullable()->comment('위임 대상 양식 (NULL=전체)');
+            $table->boolean('notify_delegator')->default(true)->comment('대결 시 보고');
+            $table->boolean('is_active')->default(true);
+            $table->string('reason', 200)->nullable()->comment('위임 사유');
+            $table->foreignId('created_by')->nullable()->constrained('users');
+            $table->softDeletes();
+            $table->timestamps();
+
+            $table->index(['tenant_id', 'delegator_id', 'is_active']);
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::dropIfExists('approval_delegations');
+    }
+};