builder.yml: Ensure consistent subuid and subgid across builders

[djgalloway]

This might explain a lot of the storage weirdness we've been observing. If a container image layer is create in rootless on podman on one machine, that image layer is restored to another host with different subuid or subgid, errors can occur.

[dmick]

mentioned in slack, but adding here for completeness:

It seems to be the case that "container images" (like you'd push) do not contain any info about the subuid/subgid mapping used to create them; they have container-internal UIDs in them that will get mapped when instantiated into a container. Do you remember what it was that broke exactly?

[djgalloway]

mentioned in slack, but adding here for completeness:

It seems to be the case that "container images" (like you'd push) do not contain any info about the subuid/subgid mapping used to create them; they have container-internal UIDs in them that will get mapped when instantiated into a container. Do you remember what it was that broke exactly?

* deleting layer "c4f15df1d80592c556020df27ca825130761cc8d71c118596d2c875a2e7305ec": unlinkat /home/jenkins-build/.local/share/containers/storage/overlay/c4f15df1d80592c556020df27ca825130761cc8d71c118596d2c875a2e7305ec/diff/usr: permission denied

time="2026-02-05T18:42:15Z" level=warning msg="Found incomplete layer \"e1503a6fd02d8ca120b20f3e7c96d1cc7c4c0add197548c6f53609fa7eb48c9f\", deleting it"

time="2026-02-05T18:42:15Z" level=warning msg="Found incomplete layer \"33d17dbb13caaf24ec94c050113b5e9b1829b9325fab0d7c150d984d9d22bb05\", deleting it"

time="2026-02-05T18:42:15Z" level=warning msg="Found incomplete layer \"99dcba4964b1a542a440e089096714bb21196c137ec6e3e7cf4a6c271261701e\", deleting it"

time="2026-02-05T18:42:15Z" level=warning msg="Found incomplete layer \"3c887834c9af32ed2b7fceb06e5f4a384ba7f9341f15c124c99fe92a0c67988c\", deleting it"

time="2026-02-05T18:42:15Z" level=warning msg="Found incomplete layer \"d7c657a5f06c8687dd8feaf400d8f6149bd8f3b6b4a08633c5e0652e771deb6c\", deleting it"

time="2026-02-05T18:42:15Z" level=warning msg="Found incomplete layer \"c4f15df1d80592c556020df27ca825130761cc8d71c118596d2c875a2e7305ec\", deleting it"

real	0m1.296s

user	0m0.919s

sys	0m0.927s

script returned exit code 125