feat: 대시보드 API 및 FCM 푸시 알림 API 구현

Dashboard API:
- DashboardController, DashboardService 추가
- /dashboard/summary, /charts, /approvals 엔드포인트

Push Notification API:
- FCM 토큰 관리 (등록/해제/목록)
- 알림 설정 관리 (유형별 on/off, 알림음 설정)
- 알림 유형: deposit, withdrawal, order, approval, attendance, notice, system
- 알림음: default, deposit, withdrawal, order, approval, urgent
- PushDeviceToken, PushNotificationSetting 모델
- Swagger 문서 추가

app/Http/Requests/Push/RegisterTokenRequest.php

@@ -0,0 +1,43 @@
+<?php
+
+namespace App\Http\Requests\Push;
+
+use App\Models\PushDeviceToken;
+use Illuminate\Foundation\Http\FormRequest;
+use Illuminate\Validation\Rule;
+
+class RegisterTokenRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    public function rules(): array
+    {
+        return [
+            'token' => ['required', 'string', 'min:10'],
+            'platform' => [
+                'required',
+                'string',
+                Rule::in([
+                    PushDeviceToken::PLATFORM_IOS,
+                    PushDeviceToken::PLATFORM_ANDROID,
+                    PushDeviceToken::PLATFORM_WEB,
+                ]),
+            ],
+            'device_name' => ['nullable', 'string', 'max:255'],
+            'app_version' => ['nullable', 'string', 'max:50'],
+        ];
+    }
+
+    public function messages(): array
+    {
+        return [
+            'token.required' => __('error.push.token_required'),
+            'token.min' => __('error.push.token_invalid'),
+            'platform.required' => __('error.push.platform_required'),
+            'platform.in' => __('error.push.platform_invalid'),
+        ];
+    }
+}