maint: prefer static_assert to verify

maint: prefer static_assert to verify

* bootstrap.conf: Add assert-h.
* gl/lib/randperm.c: Do not include verify.h.
* gl/lib/randperm.c, src/basenc.c, src/dd.c, src/digest.c:
* src/dircolors.c, src/expr.c, src/factor.c, src/ls.c, src/numfmt.c:
* src/od.c, src/seq.c, src/shred.c, src/sort.c, src/stat.c:
Prefer C23’s static_assert to nonstandard verify.
* gl/modules/randperm (Depends-on): Add assert-h.