Lockfiles in .config/

[scop]

For the same reasons why it's great that mise looks up configs from .config/, it would be good if it looked up mise.lock and mise.local.lock from there, too. This does not seem to work as of mise 2025.12.1.

https://github.com/pi0/config-dir#motivation

[jorhett]

Also reported in slightly more depth in #7343