Cause: Repair used REINSTALLMODE=ecmus. effectcraft-cli.exe has no version
resource, so Windows Installer treats it as unversioned: a changed copy
with a later write time counts as a user edit and is kept, and "c" only
checks files that carry an MSI checksum, which these don't.
Fix: Repair uses "amus", which puts back every file whatever its version
or date.
Tests: test-msi.ps1's stand-in CLI is unversioned like the real one; the
test damages it in place and repairs with the REINSTALLMODE read from
installer-ui.wxs (no longer msiexec /fa after deleting it), then compares
contents. It fails with ecmus (the damaged file stays) and passes now.
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