feat: H-2 재고 현황 API 구현

- StockController: 재고 조회 및 통계 API
- StockService: 재고 비즈니스 로직
- Stock, StockLot 모델: 재고/로트 관리
- Swagger 문서화
- stocks, stock_lots 테이블 마이그레이션

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

database/migrations/2025_12_26_132806_create_stocks_table.php

@@ -0,0 +1,74 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+/**
+ * 재고 현황 테이블
+ *
+ * 품목별 재고 현황을 관리합니다.
+ * 입고/출고 시 트리거 또는 이벤트로 자동 업데이트됩니다.
+ */
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::create('stocks', function (Blueprint $table) {
+            $table->id();
+            $table->unsignedBigInteger('tenant_id')->comment('테넌트 ID');
+
+            // 품목 정보
+            $table->string('item_code', 50)->comment('품목코드');
+            $table->string('item_name', 200)->comment('품목명');
+            $table->string('item_type', 30)->default('raw_material')
+                ->comment('품목유형: raw_material, bent_part, purchased_part, sub_material, consumable');
+            $table->string('specification', 200)->nullable()->comment('규격');
+            $table->string('unit', 20)->default('EA')->comment('단위');
+
+            // 재고 수량
+            $table->decimal('stock_qty', 15, 3)->default(0)->comment('현재 재고량');
+            $table->decimal('safety_stock', 15, 3)->default(0)->comment('안전 재고');
+            $table->decimal('reserved_qty', 15, 3)->default(0)->comment('예약 수량');
+            $table->decimal('available_qty', 15, 3)->default(0)->comment('가용 재고량');
+
+            // LOT 정보
+            $table->unsignedInteger('lot_count')->default(0)->comment('LOT 개수');
+            $table->date('oldest_lot_date')->nullable()->comment('가장 오래된 LOT 입고일');
+
+            // 위치 및 상태
+            $table->string('location', 50)->nullable()->comment('재고 위치');
+            $table->string('status', 20)->default('normal')
+                ->comment('상태: normal(정상), low(부족), out(없음)');
+
+            // 최근 입고/출고 정보
+            $table->date('last_receipt_date')->nullable()->comment('최근 입고일');
+            $table->date('last_issue_date')->nullable()->comment('최근 출고일');
+
+            // 감사 정보
+            $table->unsignedBigInteger('created_by')->nullable()->comment('생성자');
+            $table->unsignedBigInteger('updated_by')->nullable()->comment('수정자');
+            $table->timestamps();
+            $table->softDeletes();
+            $table->unsignedBigInteger('deleted_by')->nullable()->comment('삭제자');
+
+            // 인덱스
+            $table->index('tenant_id');
+            $table->index('item_code');
+            $table->index('item_type');
+            $table->index('status');
+            $table->unique(['tenant_id', 'item_code']);
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::dropIfExists('stocks');
+    }
+};

database/migrations/2025_12_26_132842_create_stock_lots_table.php

@@ -0,0 +1,76 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+/**
+ * 재고 LOT 테이블
+ *
+ * 재고의 LOT별 상세 정보를 관리합니다.
+ * FIFO 기반 출고 관리에 사용됩니다.
+ */
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::create('stock_lots', function (Blueprint $table) {
+            $table->id();
+            $table->unsignedBigInteger('tenant_id')->comment('테넌트 ID');
+            $table->unsignedBigInteger('stock_id')->comment('재고 ID');
+
+            // LOT 정보
+            $table->string('lot_no', 50)->comment('LOT번호');
+            $table->unsignedInteger('fifo_order')->default(1)->comment('FIFO 순서');
+            $table->date('receipt_date')->comment('입고일');
+
+            // 수량 정보
+            $table->decimal('qty', 15, 3)->default(0)->comment('수량');
+            $table->decimal('reserved_qty', 15, 3)->default(0)->comment('예약 수량');
+            $table->decimal('available_qty', 15, 3)->default(0)->comment('가용 수량');
+            $table->string('unit', 20)->default('EA')->comment('단위');
+
+            // 공급업체 정보
+            $table->string('supplier', 100)->nullable()->comment('공급업체');
+            $table->string('supplier_lot', 50)->nullable()->comment('공급업체 LOT');
+            $table->string('po_number', 50)->nullable()->comment('발주번호');
+
+            // 위치 및 상태
+            $table->string('location', 50)->nullable()->comment('위치');
+            $table->string('status', 20)->default('available')
+                ->comment('상태: available(사용가능), reserved(예약됨), used(사용완료)');
+
+            // 연결 정보
+            $table->unsignedBigInteger('receiving_id')->nullable()->comment('입고 ID');
+
+            // 감사 정보
+            $table->unsignedBigInteger('created_by')->nullable()->comment('생성자');
+            $table->unsignedBigInteger('updated_by')->nullable()->comment('수정자');
+            $table->timestamps();
+            $table->softDeletes();
+            $table->unsignedBigInteger('deleted_by')->nullable()->comment('삭제자');
+
+            // 인덱스
+            $table->index('tenant_id');
+            $table->index('stock_id');
+            $table->index('lot_no');
+            $table->index('status');
+            $table->index(['stock_id', 'fifo_order']);
+            $table->unique(['tenant_id', 'stock_id', 'lot_no']);
+
+            // 외래키
+            $table->foreign('stock_id')->references('id')->on('stocks')->onDelete('cascade');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::dropIfExists('stock_lots');
+    }
+};