Add {{.Temp}} variable to host templates

[jandubois]

Note

For discussion purposes; would need to apply changes to all templates if accepted.

See #2339 (comment) and #3316.

Allows writing the /tmp/lima mount as

mounts:
- location: "{{.Temp}}/lima"
  mountPoint: /tmp/lima

Note that on macOS this would use $TMPDIR and not /tmp, so would be a change in behaviour. It would not affect existing instances though.

[afbjorklund]

Do you need to model "the real" $TMPDIR, or should it be something like $LIMA_TEMP instead?

One concern was that there are many users sharing the /tmp/lima location, on a shared server.

[arixmkii]

This made default.yaml compatible with Windows. I managed to create and start VM w/o changes to template.

Output of the mount command:

C:\msys64\home\Arthu\gitrepos\lima\_output\bin>limactl shell default mount | find "sshfs"
time="2025-03-08T20:21:48+02:00" level=warning msg="treating lima version \"e0487475.m\" from \"C:\\\\Users\\\\Arthu\\\\.lima\\\\default\\\\lima-version\" as very latest release"
bash: line 1: cd: /mnt/c/msys64/home/Arthu/gitrepos/lima/_output/bin: No such file or directory
:/mnt/c/Users/Arthu on /mnt/c/Users/Arthu type fuse.sshfs (ro,nosuid,nodev,relatime,user_id=1000,group_id=1000,allow_other)
:/mnt/c/Users/Arthu/AppData/Local/Temp/lima on /tmp/lima type fuse.sshfs (rw,nosuid,nodev,relatime,user_id=1000,group_id=1000,allow_other)

The /mnt/ prefixes come from WSL2 Alpine tools container (wslpath instead of cygpath), which I use for running QEMU. I'm yet to figure out required fixes to run it with Git bash msys2 stack (mux modes are not supported in msys2 OpenSSH).

[arixmkii]

9p mounts

C:\msys64\home\Arthu\gitrepos\lima\_output\bin>limactl shell default mount | find "9p"
time="2025-03-08T20:36:53+02:00" level=warning msg="treating lima version \"e0487475.m\" from \"C:\\\\Users\\\\Arthu\\\\.lima\\\\default\\\\lima-version\" as very latest release"
bash: line 1: cd: /mnt/c/msys64/home/Arthu/gitrepos/lima/_output/bin: No such file or directory
mount0 on /mnt/c/Users/Arthu type 9p (ro,relatime,cache=8f,access=client,msize=131072,trans=virtio)
mount1 on /tmp/lima type 9p (rw,relatime,cache=5,access=client,msize=131072,trans=virtio)

[jandubois]

I'm going to leave this PR open (and in draft mode) because I think adding the {{.Temp}} variable and normalizing mountpoints is something we should eventually merge.

But the change to templates/default.yaml seems wrong to me and should not be merged! We need further discussion to figure out how to deal with this. I'll be offline from Mar 13 to 31, so can't participate until next month.