I presume that Tailscale will stay at 1.24.2 in OpenWRT 21.02 for the lifetime of that release. Correct?
It could be, but Tailscale should be updated in the OpenWrt master branch, and then it could be backported. Still, since the newer Tailscale version requires a newer version of Golang, thus it could be complicated to have it backported to OpenWrt 21.02, so you will see if you will create a pull request to OpenWrt packages feed.
I presume that Tailscale will stay at 1.24.2 in TOS until TOS upgrades to a newer OpenWRT. Correct?
As I said, currently, in all OpenWrt supported versions, there is the same version of Tailscale. If someone updates it in the meantime in OpenWrt 22.03, then you will see the new Tailscale version once we update Turris OS to OpenWrt 22.03. Otherwise, the version would be the same if nobody steps in.
Given the pace of Tailscale development, if we wanted to ensure that TOS has a version of Tailscale that is as up to date as possible (TBD what “possible” means), how would we go about it?
Short version: The community should step it, and prepare OpenWrt build system, or you can use scripts to prepare the Turris environment. You need to get familiar with how to compile packages for OpenWrt. Then you can test it on your router, upstream it.
That will be closed immediately since this does not belong to our GitLab as I said in the first place because it is an upstream issue not ours.