Two failure modes found while validating the harness against a scratch
config root:
Teardown removed $dest unconditionally before restoring the backup, so
a second run deleted the user's own file — the first run had already
restored it, and a restored original is indistinguishable from an
installed demo file except by content. Compare against the source
before removing.
Setup had the mirror-image bug: run twice without an intervening
teardown it backed up its *own* copy, and teardown then "restored"
that, leaving demo.md in the user's config permanently. Treat an
already-identical destination as a no-op.
Also fail fast when bot-bottle is not on PATH. The tape types the real
console script, so without it a recording silently captures
`command not found` instead of a bottle launching.
Refs #540
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
didericis
f23086171b