feat: [finance] 계정별원장·손익계산서 API 추가

- GET /api/v1/account-ledger: 계정별원장 조회 (이월잔액, 월별소계/누계)
- GET /api/v1/income-statement: 손익계산서 조회 (당기/전기 비교, 단위변환)
- KIS 표준 계정과목 sub_category 기반 자동 매핑
- 일반전표 + 홈택스 분개 UNION ALL 통합 집계

app/Http/Controllers/Api/V1/AccountLedgerController.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace App\Http\Controllers\Api\V1;
+
+use App\Helpers\ApiResponse;
+use App\Http\Controllers\Controller;
+use App\Services\AccountLedgerService;
+use Illuminate\Http\Request;
+
+class AccountLedgerController extends Controller
+{
+    public function __construct(
+        private readonly AccountLedgerService $service
+    ) {}
+
+    /**
+     * 계정별원장 조회
+     */
+    public function index(Request $request)
+    {
+        $request->validate([
+            'start_date' => 'required|date',
+            'end_date' => 'required|date|after_or_equal:start_date',
+            'account_code' => 'required|string|max:10',
+        ]);
+
+        return ApiResponse::handle(function () use ($request) {
+            return $this->service->index($request->only(['start_date', 'end_date', 'account_code']));
+        }, __('message.fetched'));
+    }
+}

app/Http/Controllers/Api/V1/IncomeStatementController.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace App\Http\Controllers\Api\V1;
+
+use App\Helpers\ApiResponse;
+use App\Http\Controllers\Controller;
+use App\Services\IncomeStatementService;
+use Illuminate\Http\Request;
+
+class IncomeStatementController extends Controller
+{
+    public function __construct(
+        private readonly IncomeStatementService $service
+    ) {}
+
+    /**
+     * 손익계산서 조회
+     */
+    public function index(Request $request)
+    {
+        $request->validate([
+            'start_date' => 'required|date',
+            'end_date' => 'required|date|after_or_equal:start_date',
+            'unit' => 'nullable|in:won,thousand,million',
+        ]);
+
+        return ApiResponse::handle(function () use ($request) {
+            return $this->service->data($request->only(['start_date', 'end_date', 'unit']));
+        }, __('message.fetched'));
+    }
+}