Wait status is total

Unix wait results remain typed without ceasing to be total: rustix’s transparent WaitStatus carries every kernel status, while one retrying funnel makes EINTR unobservable to lifecycle code.

Decision

• Blocking and polling are different doors. waitpid_eintr / waitpgid_eintr return Result<(Pid, WaitStatus), Errno>; try_waitpid_eintr / try_waitpgid_eintr alone return Option. The doors own NOHANG, so an impossible idle result cannot leak into a blocking caller.
• The doors retry EINTR internally. A signal delivery therefore cannot look like ECHILD and erase a live job.
• Consumers classify through WaitStatus’s bit-test accessors. Unclassifiable and continued statuses retain their raw code where the surrounding outcome vocabulary has no dedicated case.
• Process and process-group waits are distinct functions; callers never encode a process group by negating an integer pid. Pgid itself admits only positive identifiers, so the conversion to rustix’s Pid is proved once by the type.

Rejected shape

nix::sys::wait::WaitStatus is a fallible enum conversion, not a total view of the kernel word. Its decode can reject real-time terminating signals, and an internal assertion gives an unfamiliar status a panic path. A shell’s reaper must accept every status the kernel can produce; rustix’s transparent wrapper preserves that law.

Consequences

• ral/src/jobs.rs contains neither libc flags nor WIF* decoding.
• The raw (pid, status) sentinel convention disappears from core/src/process/signal/unix.rs.
• Error rendering is unchanged: rustix Errno converts to the same OS error text at the existing std::io::Result boundary.

See process and REPL jobs.