fix(multi): apply merlint fixes for yamlt, zephyr, space-wire, tls
- ocaml-yamlt: rename make_decoder->decoder, make_encoder->encoder; fix doc
arg counts; add test dir with test_yamlt.ml
- ocaml-zephyr: extract check_sysfs_entry helper to reduce nesting depth;
add test dir with test_zephyr.ml
- space-wire: extract roundtrip_test/crash_test helpers to shorten fuzz suite;
add fuzz_space_wire.mli docs
- ocaml-tls: Printf.eprintf -> Fmt.epr in test_helpers.ml