Use entry metadata to discover registration evidence independently of target
readability. Preserve failed metadata inspection as a named invalid diagnostic
instead of treating all lookup failures as absence. Remove the duplicate
boolean existence wrapper; configuration parsing remains the read owner.
Cover native permission-denied targets and metadata, dangling configuration
entries, maintenance exclusion, and public doctor output without mutation.
Validation: 73 focused tests across four files, check:fast, format:check,
and six isolated completed public doctor cost comparisons passed on macOS
arm64 / Node24.18.0. Native Windows/Linux permissions were not verified;
POSIX permission controls skip unsupported hosts and root.
Fixes#4905
Report malformed Hermes and DeepSeek Harness documents as YAML. Carry the
compiled setup/uninstall diagnostics coverage from #2153 onto the existing
validation from #2157, including unchanged files and no backup writes.
Add malformed YAML scenarios for both clients.
Validation: 174 focused tests, npm run check, test discovery, package
verification, and npm pack --dry-run.
Co-authored-by: Jax367 <239124526+Jax367@users.noreply.github.com>
morluto