aliases: rename now propagates every meta.json I/O and parse error
instead of silently ignoring failures. Previously, a corrupt or
unreadable meta.json after directory rename would leave the alias
in an inconsistent state with no user-visible error.
doctor: Config::load failure now falls back to Config::default()
with a warning instead of aborting the entire health check. Doctor
should still run diagnostics even when config is missing or corrupt
— that's exactly when you need it most.
