erlang-runtime: add lib/erlang/runtime.sx + test.sh (55/55 pass)
Numeric tower (is-integer?/float?/number?, float/trunc/round/abs/max/min),
div/rem (quotient/remainder), bitwise (band/bor/bxor/bnot/bsl/bsr),
sets module (new/add/member/union/intersection/subtract/size/to-list/from-list),
re module (run/replace/replace-all/match-groups/split),
list BIFs (hd/tl/length/member/reverse/nth/foldl/foldr/seq/flatten/zip),
type conversions (integer-to-list, list-to-integer, atom-to-list, etc.),
ok/error tuple helpers.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
giles
3c0a963229