* fix(plugins): isolate development watcher retries by root
* test(plugins): keep coverage for late binding checks after housekeeping disposal
The per-root rewrite replaced the old housekeeping unit tests; restore the
disposal/coalescing case so a slow check that resolves after dispose cannot
restart a watcher or refresh, and per-root checks do not stack.
* fix(plugins): skip the full plugin rediscovery while a dev folder retry keeps failing
A maintenance retry that subscribes already refreshes itself; one that keeps failing (an
unreachable WSL share) rediscovered every plugin each tick. Only a changed root binding needs
discovery now.
Also covers what the per-root rewrite must keep: adding/removing a folder leaves the others'
watchers and frame revisions alone and releases its subscriptions, a rejecting registration
retries once per tick, Linux sibling folders keep separate parent watches, and an Electron e2e
where deleting/recreating/removing one dev folder never reloads another folder's open panel.
---------
Co-authored-by: be0hhh <182023099+be0hhh@users.noreply.github.com>
Co-authored-by: Neil <neil@stably.ai>
