Every surviving carrier now owns its artifacts: checked mkdir/mkdtemp/
fopen acquisition, one all-exit cleanup funnel per carrier, ENOENT-
tolerant checked unlinks, exact-path deletion (rm -rf only for an
owned pid-keyed dir or a .sepwork beneath one), and cleanup failure
fails a passing carrier without overwriting its diagnostic. In the
same pass the carriers adapt to the driver contract this branch lands:
--sep and WW_PKGCACHE are gone, -S and the /tmp/ww_run_<pid> scratch
contract are asserted, and rows whose runtime or reject coverage moved
to test/wcc/data fixtures or test/lang @test owners are trimmed to the
byte/artifact/diagnostic observations only they can make.
Repair and adaptation ride together because most files interleave both
in the same hunks; splitting would manufacture intermediate carrier
states that never existed and cannot run against either driver.
The N_TTAGGED serializer emitted each variant via wwi_type but never
re-emitted the `...` prefix for TK_ELLIPSIS spread variants, so an
exported `(...inner | str)` round-tripped through .wwi as `(inner | str)`.
The consumer's checker then could not flatten inner's members into the
alias and variadic-assignability rejected bare members — under separate
compilation this broke fmt/log/getopt. Re-emit `...` before the variant
type, both stages; the producer stays purely syntactic (flatten/dedup
remain the consumer's type-store job, per ref/hare/hare/unparse/type.ha:290-300).
Gate: test/wcc/989_wwispread_sep.c — table-driven (2-arm + 3-arm spreads)
x both stages, asserts the marker survives the .wwi, the consumer binds
bare members under --sep (exit 0), and cs==ww .wwi byte-identity.
