iyi 0.5.1

The language reached the machine most developers sit in front of, and a caught panic stopped costing the process.

darwin arm64 is a run target and a ship target: the same fibers, defer
registry and panic path, calling libSystem where Linux issues raw
syscalls — Apple's rule, not a compromise — with a native CI job
holding the same gates and shipping its own relocatable tarball,
proven by unpacking it somewhere else and running the prelude,
--crystal and the daemon out of it.

And III.1.4's last sentence went literal: reading a panicked task's
handle catches the panic as a Panicked value and the process outlives
the bug; a panic nobody reads is still re-raised at the join, exactly
once.

.iyimod format is unchanged at 41; a 0.5.0 artifact is rejected by a
0.5.1 build and rebuilt, never migrated. Both tarballs below were
built and proven by the tagged run itself.

Extract, put bin on PATH: iyi run, iyi lsp, iyi vet — nothing to
configure.