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/Models/PushDeviceToken.php

@@ -0,0 +1,79 @@
+<?php
+
+namespace App\Models;
+
+use App\Traits\BelongsToTenant;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\SoftDeletes;
+
+class PushDeviceToken extends Model
+{
+    use BelongsToTenant;
+    use SoftDeletes;
+
+    protected $fillable = [
+        'tenant_id',
+        'user_id',
+        'token',
+        'platform',
+        'device_name',
+        'app_version',
+        'is_active',
+        'last_used_at',
+    ];
+
+    protected $casts = [
+        'is_active' => 'boolean',
+        'last_used_at' => 'datetime',
+    ];
+
+    /**
+     * 플랫폼 상수
+     */
+    public const PLATFORM_IOS = 'ios';
+
+    public const PLATFORM_ANDROID = 'android';
+
+    public const PLATFORM_WEB = 'web';
+
+    /**
+     * 사용자 관계
+     */
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+
+    /**
+     * 테넌트 관계
+     */
+    public function tenant(): BelongsTo
+    {
+        return $this->belongsTo(Tenant::class);
+    }
+
+    /**
+     * Scope: 활성 토큰만
+     */
+    public function scopeActive($query)
+    {
+        return $query->where('is_active', true);
+    }
+
+    /**
+     * Scope: 플랫폼별 필터
+     */
+    public function scopePlatform($query, string $platform)
+    {
+        return $query->where('platform', $platform);
+    }
+
+    /**
+     * Scope: 특정 사용자의 토큰
+     */
+    public function scopeForUser($query, int $userId)
+    {
+        return $query->where('user_id', $userId);
+    }
+}