The manifest gains `assets` (linux-x64 / windows-x64 → archive URL);
top-level `url` stays the Linux tarball for 0.2.1 installs. A Windows-
only test applies a bsdtar zip over a running exe (PING.EXE copy) and
checks it is parked as .old and swept next start; Linux-layout tests
(exec bits, symlinks) skip on Windows.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>