createBatcher collects distinct requests within a window/maxSize and
dispatches them together. onExternalInvalidate fires unconditionally
from invalidateTags/invalidateKeys so a bridge package can translate
protocol push invalidation into an external cache's own invalidation
call, even for keys this cache holds no local entry for. bridge.ts
documents the tag/key -> queryKey translation contract bridge packages
will share.

Bumps to 0.1.0-rc.4.