Function GET

Returns Promise<
    | NextResponse<
        {
            overview: {
                total: number;
                active: number;
                completed: number;
                inProgress: number;
                planned: number;
                cancelled: number;
                completionRate: number;
                totalCost: number;
            };
            byType: { type: string; count: number }[];
            byStatus: { status: string; count: number }[];
            upcoming: {
                id: string;
                title: string;
                startDate: Date | null;
                participants: number;
            }[];
            recent: {
                id: string;
                title: string;
                completionDate: Date
                | null;
                participants: number;
            }[];
            mostPopular: | {
                _count: { employeeTrainings: number };
                id: string;
                title: string;
            }
            | null;
        },
    >
    | NextResponse<{ error: string }>,
>