将上面的数组生成一个树形管理权限结构数组

$permissions = [
    [
        'id' => 1,
        'name' => '用户管理',
        'pid' => 0,
        'children' => [
            [
                'id' => 2,
                'name' => '添加用户',
                'pid' => 1,
                'children' => []
            ],
            [
                'id' => 3,
                'name' => '修改用户',
                'pid' => 1,
                'children' => []
            ],
            [
                'id' => 4,
                'name' => '删除用户',
                'pid' => 1,
                'children' => []
            ]
        ]
    ],
    [
        'id' => 5,
        'name' => '角色管理',
        'pid' => 0,
        'children' => [
            [
                'id' => 6,
                'name' => '添加角色',
                'pid' => 5,
                'children' => []
            ],
            [
                'id' => 7,
                'name' => '修改角色',
                'pid' => 5,
                'children' => []
            ],
            [
                'id' => 8,
                'name' => '删除角色',
                'pid' => 5,
                'children' => []
            ]
        ]
    ],
    [
        'id' => 9,
        'name' => '权限管理',
        'pid' => 0,
        'children' => [
            [
                'id' => 10,
                'name' => '添加权限',
                'pid' => 9,
                'children' => []
            ],
            [
                'id' => 11,
                'name' => '修改权限',
                'pid' => 9,
                'children' => []
            ],
            [
                'id' => 12,
                'name' => '删除权限',
                'pid' => 9,
                'children' => []
            ]
        ]
    ]
];