feat: 매입관리 품의서/지출결의서 연동 기능 추가

- purchases 테이블에 approval_id 컬럼 추가 (마이그레이션)
- Purchase 모델에 approval 관계 정의
- PurchaseService에서 approval 데이터 eager loading 구현
- FormRequest에 approval_id 유효성 검증 추가
- Swagger 문서에 approval 관련 스키마 추가

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

app/Services/PurchaseService.php

@@ -17,7 +17,7 @@ public function index(array $params): LengthAwarePaginator
 
         $query = Purchase::query()
             ->where('tenant_id', $tenantId)
-            ->with(['client:id,name']);
+            ->with(['client:id,name', 'approval:id,document_number,title,form_id', 'approval.form:id,name,category']);
 
         // 검색어 필터
         if (! empty($params['search'])) {
@@ -69,7 +69,7 @@ public function show(int $id): Purchase
 
         return Purchase::query()
             ->where('tenant_id', $tenantId)
-            ->with(['client:id,name', 'withdrawal', 'creator:id,name'])
+            ->with(['client:id,name', 'withdrawal', 'creator:id,name', 'approval:id,document_number,title,form_id,content', 'approval.form:id,name,category'])
             ->findOrFail($id);
     }
 
@@ -97,6 +97,7 @@ public function store(array $data): Purchase
             $purchase->description = $data['description'] ?? null;
             $purchase->status = 'draft';
             $purchase->withdrawal_id = $data['withdrawal_id'] ?? null;
+            $purchase->approval_id = $data['approval_id'] ?? null;
             $purchase->created_by = $userId;
             $purchase->updated_by = $userId;
             $purchase->save();
@@ -154,6 +155,9 @@ public function update(int $id, array $data): Purchase
             if (array_key_exists('tax_invoice_received', $data)) {
                 $purchase->tax_invoice_received = $data['tax_invoice_received'];
             }
+            if (array_key_exists('approval_id', $data)) {
+                $purchase->approval_id = $data['approval_id'];
+            }
 
             $purchase->updated_by = $userId;
             $purchase->save();
@@ -302,6 +306,123 @@ public function bulkUpdateTaxReceived(array $ids, bool $taxInvoiceReceived): int
             ]);
     }
 
+    /**
+     * 대시보드 상세 조회 (CEO 대시보드 모달용)
+     *
+     * @return array{
+     *     summary: array{current_month_total: float, previous_month_total: float, change_rate: float, count: int},
+     *     monthly_trend: array<array{month: string, amount: float}>,
+     *     by_type: array<array{type: string, label: string, amount: float, ratio: float}>,
+     *     items: array<array{id: int, date: string, vendor_name: string, amount: float, type: string, type_label: string}>
+     * }
+     */
+    public function dashboardDetail(): array
+    {
+        $tenantId = $this->tenantId();
+
+        // 현재 월 범위
+        $currentMonthStart = now()->startOfMonth()->toDateString();
+        $currentMonthEnd = now()->endOfMonth()->toDateString();
+
+        // 전월 범위
+        $previousMonthStart = now()->subMonth()->startOfMonth()->toDateString();
+        $previousMonthEnd = now()->subMonth()->endOfMonth()->toDateString();
+
+        // 1. 요약 정보
+        $currentMonthTotal = Purchase::query()
+            ->where('tenant_id', $tenantId)
+            ->whereBetween('purchase_date', [$currentMonthStart, $currentMonthEnd])
+            ->sum('total_amount');
+
+        $previousMonthTotal = Purchase::query()
+            ->where('tenant_id', $tenantId)
+            ->whereBetween('purchase_date', [$previousMonthStart, $previousMonthEnd])
+            ->sum('total_amount');
+
+        $currentMonthCount = Purchase::query()
+            ->where('tenant_id', $tenantId)
+            ->whereBetween('purchase_date', [$currentMonthStart, $currentMonthEnd])
+            ->count();
+
+        $changeRate = $previousMonthTotal > 0
+            ? round((($currentMonthTotal - $previousMonthTotal) / $previousMonthTotal) * 100, 1)
+            : 0;
+
+        // 2. 월별 추이 (최근 7개월)
+        $monthlyTrend = [];
+        for ($i = 6; $i >= 0; $i--) {
+            $monthStart = now()->subMonths($i)->startOfMonth();
+            $monthEnd = now()->subMonths($i)->endOfMonth();
+
+            $amount = Purchase::query()
+                ->where('tenant_id', $tenantId)
+                ->whereBetween('purchase_date', [$monthStart->toDateString(), $monthEnd->toDateString()])
+                ->sum('total_amount');
+
+            $monthlyTrend[] = [
+                'month' => $monthStart->format('Y-m'),
+                'amount' => (float) $amount,
+            ];
+        }
+
+        // 3. 유형별 분포 (현재 월)
+        $byTypeRaw = Purchase::query()
+            ->where('tenant_id', $tenantId)
+            ->whereBetween('purchase_date', [$currentMonthStart, $currentMonthEnd])
+            ->select('purchase_type', DB::raw('SUM(total_amount) as amount'))
+            ->groupBy('purchase_type')
+            ->get();
+
+        $byType = [];
+        $totalAmount = $byTypeRaw->sum('amount');
+
+        foreach ($byTypeRaw as $item) {
+            $type = $item->purchase_type ?? 'unset';
+            $byType[] = [
+                'type' => $type,
+                'label' => Purchase::PURCHASE_TYPES[$type] ?? '미설정',
+                'amount' => (float) $item->amount,
+                'ratio' => $totalAmount > 0 ? round(($item->amount / $totalAmount) * 100, 1) : 0,
+            ];
+        }
+
+        // ratio 내림차순 정렬
+        usort($byType, fn ($a, $b) => $b['ratio'] <=> $a['ratio']);
+
+        // 4. 일별 매입 내역 (현재 월)
+        $items = Purchase::query()
+            ->where('tenant_id', $tenantId)
+            ->whereBetween('purchase_date', [$currentMonthStart, $currentMonthEnd])
+            ->with(['client:id,name'])
+            ->orderBy('purchase_date', 'desc')
+            ->get()
+            ->map(function ($purchase) {
+                $type = $purchase->purchase_type ?? 'unset';
+
+                return [
+                    'id' => $purchase->id,
+                    'date' => $purchase->purchase_date->format('Y-m-d'),
+                    'vendor_name' => $purchase->client?->name ?? '-',
+                    'amount' => (float) $purchase->total_amount,
+                    'type' => $type,
+                    'type_label' => Purchase::PURCHASE_TYPES[$type] ?? '미설정',
+                ];
+            })
+            ->toArray();
+
+        return [
+            'summary' => [
+                'current_month_total' => (float) $currentMonthTotal,
+                'previous_month_total' => (float) $previousMonthTotal,
+                'change_rate' => $changeRate,
+                'count' => $currentMonthCount,
+            ],
+            'monthly_trend' => $monthlyTrend,
+            'by_type' => $byType,
+            'items' => $items,
+        ];
+    }
+
     /**
      * 매입번호 자동 생성
      */