On git-channel installs where both extensions/<id>/index.ts and
dist/extensions/<id>/index.js exist, two registry assemblies resolved the same
plugin id to different physical files (preferBuiltPluginArtifacts drives both the
artifact choice and the load-cache key), so the path-keyed module cache
evaluated the entry twice — two live plugin instances with separate state,
binding hooks to one and registerTool to the other. Memoize the first resolved
runtime entry path per plugin-id + real root + entry-kind so both assemblies
converge on one module instance; clear the memo on activated-runtime-state and
registry-load-cache resets so reload/install/doctor re-resolve. No-op on
dist-only installs.
Closes#107933
