* fix(doctor): archive legacy clawd browser profile residue
* Avoid browser cleanup load without residue
Doctor --fix now skips loading the browser doctor facade unless the legacy browser/clawd profile path exists, preventing broad config repair tests from paying the plugin load cost when there is nothing to archive.
* Use structured health check for browser residue
Register the legacy clawd browser profile residue cleanup through the modern doctor health-check contract so doctor --lint can report it and doctor --fix repairs it through structured effects.
