install from this checkout via RIG_INSTALL_SOURCE, assert what landed,
a converging re-run proven by an empty diff, uninstall --all ending in
the absence assert (! -e AND ! -L). test/install-lifecycle.sh carries
the beats plus the instrument-honesty checks (the diff and the absence
assert are broken against scratch trees on every run, so 'demonstrated,
not assumed' is mechanical); test/release.sh gains the local channel's
contract — dir, tarball, loud refusal, never a silent download fallback.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>