feat(api): 예상비용 동기화 커맨드 및 서비스 개선

- SyncExpectedExpensesCommand 추가
- ExpectedExpenseService 로직 개선
- LOGICAL_RELATIONSHIPS 문서 업데이트

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

app/Services/ExpectedExpenseService.php

@@ -312,6 +312,8 @@ public function summary(array $params): array
      *         remaining_balance: float,
      *         item_count: int
      *     },
+     *     monthly_trend: array,
+     *     vendor_distribution: array,
      *     items: array,
      *     footer_summary: array
      * }
@@ -356,7 +358,13 @@ public function dashboardDetail(?string $transactionType = null): array
             ->where('payment_status', 'pending')
             ->sum('amount');
 
-        // 2. 지출예상 목록 (당월, 지급일 순)
+        // 2. 월별 추이 (최근 7개월)
+        $monthlyTrend = $this->getMonthlyTrend($tenantId, $transactionType);
+
+        // 3. 거래처별 분포 (당월, 상위 5개)
+        $vendorDistribution = $this->getVendorDistribution($tenantId, $transactionType, $currentMonthStart, $currentMonthEnd);
+
+        // 4. 지출예상 목록 (당월, 지급일 순)
         $itemsQuery = ExpectedExpense::query()
             ->select([
                 'expected_expenses.id',
@@ -394,7 +402,7 @@ public function dashboardDetail(?string $transactionType = null): array
             })
             ->toArray();
 
-        // 3. 푸터 합계
+        // 5. 푸터 합계
         $footerSummary = [
             'total_amount' => (float) $currentMonthTotal,
             'item_count' => count($items),
@@ -407,8 +415,111 @@ public function dashboardDetail(?string $transactionType = null): array
                 'change_rate' => $changeRate,
                 'remaining_balance' => (float) $pendingBalance,
             ],
+            'monthly_trend' => $monthlyTrend,
+            'vendor_distribution' => $vendorDistribution,
             'items' => $items,
             'footer_summary' => $footerSummary,
         ];
     }
+
+    /**
+     * 월별 추이 데이터 조회 (최근 7개월)
+     */
+    private function getMonthlyTrend(int $tenantId, ?string $transactionType = null): array
+    {
+        $months = [];
+        for ($i = 6; $i >= 0; $i--) {
+            $date = now()->subMonths($i);
+            $months[] = [
+                'month' => $date->format('Y-m'),
+                'label' => $date->format('n') . '월',
+                'start' => $date->startOfMonth()->toDateString(),
+                'end' => $date->endOfMonth()->toDateString(),
+            ];
+        }
+
+        $result = [];
+        foreach ($months as $month) {
+            $query = ExpectedExpense::query()
+                ->where('tenant_id', $tenantId)
+                ->whereBetween('expected_payment_date', [$month['start'], $month['end']]);
+
+            if ($transactionType) {
+                $query->where('transaction_type', $transactionType);
+            }
+
+            $amount = $query->sum('amount');
+
+            $result[] = [
+                'month' => $month['month'],
+                'label' => $month['label'],
+                'amount' => (float) $amount,
+            ];
+        }
+
+        return $result;
+    }
+
+    /**
+     * 거래처별 분포 데이터 조회 (상위 N개 + 기타)
+     */
+    private function getVendorDistribution(int $tenantId, ?string $transactionType, string $startDate, string $endDate, int $limit = 5): array
+    {
+        $query = ExpectedExpense::query()
+            ->select(
+                DB::raw("COALESCE(client_name, '미지정') as vendor_name"),
+                DB::raw('SUM(amount) as total_amount'),
+                DB::raw('COUNT(*) as count')
+            )
+            ->where('tenant_id', $tenantId)
+            ->whereBetween('expected_payment_date', [$startDate, $endDate])
+            ->groupBy('client_name')
+            ->orderByDesc('total_amount');
+
+        if ($transactionType) {
+            $query->where('transaction_type', $transactionType);
+        }
+
+        $all = $query->get();
+
+        // 전체 합계
+        $totalSum = $all->sum('total_amount');
+        if ($totalSum <= 0) {
+            return [];
+        }
+
+        // 상위 N개
+        $top = $all->take($limit);
+        $topSum = $top->sum('total_amount');
+
+        // 색상 팔레트
+        $colors = ['#60A5FA', '#34D399', '#FBBF24', '#F87171', '#A78BFA', '#94A3B8'];
+
+        $result = [];
+        foreach ($top as $index => $item) {
+            $percentage = round(($item->total_amount / $totalSum) * 100, 1);
+            $result[] = [
+                'name' => $item->vendor_name,
+                'value' => (float) $item->total_amount,
+                'count' => (int) $item->count,
+                'percentage' => $percentage,
+                'color' => $colors[$index] ?? '#94A3B8',
+            ];
+        }
+
+        // 기타 (나머지 합산)
+        $othersSum = $totalSum - $topSum;
+        if ($othersSum > 0 && $all->count() > $limit) {
+            $othersCount = $all->skip($limit)->sum('count');
+            $result[] = [
+                'name' => '기타',
+                'value' => (float) $othersSum,
+                'count' => (int) $othersCount,
+                'percentage' => round(($othersSum / $totalSum) * 100, 1),
+                'color' => '#94A3B8',
+            ];
+        }
+
+        return $result;
+    }
 }