Yggdrasil trackers don't work with ZeroNet

I tried setting up my own Yggdrasil tracker and using Neil Alexander's tracker. Neither work even on IPv6 internet connectivity. I'm using an unmodified version of ZeroNet, ZeroNet Mobile from the Play Store.

Neil Alexander's tracker is ```http://[300:7232:2b0e:d6e9:216:3eff:fe34:ec44]:6969/announce```

Rev 4555

Start by reproducing the failure with both the reporter's Yggdrasil tracker and Neil Alexander's tracker URL on ZeroNet Mobile, using the reported Rev 4555 context. Compare tracker setup and announce behavior over IPv6; done means a ZeroNet tracker successfully responds to announces, with the failing path and reproduction details documented.

索引モデルが issue の本文から書いたものです。