IPv6 does not work in Windows TUN device

[cruse123]

IPv6 single stack or dual stack does not work in Windows TUN device.

Server side (linux amd64):

$ ./gost -V
gost v3.0.0-nightly.20241211 (go1.23.4 linux/amd64)

$ sudo ./gost -L=tun://:8421?net=fd::1/64
{"handler":"tun","kind":"service","level":"info","listener":"tun","msg":"listening on :8421/udp","service":"service-0","time":"2024-12-16T12:01:56.352+08:00"}
{"handler":"tun","kind":"listener","level":"info","listener":"tun","msg":"name: tun0, net: fd::1, mtu: 1350, addrs: [fd::1/64 fe80::e006:c7ef:64fb:7e38/64]","service":"service-0","time":"2024-12-16T12:01:56.356+08:00"}
{"handler":"tun","kind":"handler","level":"info","listener":"tun","local":":8421","msg":"fd::1 <> :8421","remote":"fd::1","service":"service-0","sid":"ctfqcd569hhbri3moong","time":"2024-12-16T12:01:56.357+08:00"}

Client side (windows amd64, with wintun 0.14.1):
With single IPv6 stack, the TUN device fails and retries indefinitely.

> gost -V
gost v3.0.0-nightly.20241211 (go1.23.4 windows/amd64)

> gost -L=tun://:0/192.168.xx.xx:8421?net=fd::2/64
{"handler":"tun","kind":"service","level":"info","listener":"tun","msg":"listening on :0/udp","service":"service-0","time":"2024-12-16T12:01:58.750+08:00"}
2024/12/16 12:01:59.037316 wintun.go:51: Using existing driver 0.14
2024/12/16 12:01:59.048721 wintun.go:51: Creating adapter
2024/12/16 12:01:59.966483 wintun.go:51: Removed orphaned adapter "wintun 1"
2024/12/16 12:02:00.262774 wintun.go:51: Failed to remove adapter when closing: The device instance does not exist in the hardware tree. (Code 0xE000020B)
{"handler":"tun","kind":"listener","level":"error","listener":"tun","msg":"netsh interface ip set address name=wintun source=static addr=fd::2 mask=255.255.255.255 gateway=none: exit status 1","service":"service-0","time":"2024-12-16T12:02:00.263+08:00"}
2024/12/16 12:02:00.371207 wintun.go:51: Removed orphaned adapter "wintun"

(indefinite loops...)

With v4+v6 dual stack (net=192.168.123.1/24,fd::1/64 for server, net=192.168.123.1/24,fd::2/64 for client), the client gost successfully starts, but IPv6 traffic is not working.