Lint

[codex] Use assert_never for enum fallbacks #7885

Job	Run time
build (3.14, windows-latest, manual)	1m 43s
build (3.14, windows-latest, pre-commit)	2m 22s
build (3.14, ubuntu-latest, pre-commit)	56s
build (3.14, ubuntu-latest, manual)	52s
build (3.14, ubuntu-latest, pre-push)	5m 41s
build (3.14, windows-latest, pre-push)	8m 32s
completion-lint	2s
	20m 8s

Provide feedback