feat: notice bundles as they arrive, and let the reader add them

The bundles directory is now watched: a .atlas file dropped in, replaced
with a newer build, or deleted is noticed within a moment, rescanned,
and announced to the frontend as one atlas:catalog-changed event through
the application's own bus. The frontend reconciles rather than reloads.
A game that arrived is offered; the game being read, replaced by a newer
build, reloads through the new stamped URLs carrying the camera, the
filters, and the panels across, so an update reads as the map sharpening
rather than the application starting over; a game that left gives way,
and an empty library shows a quiet card naming the directory bundles go
in rather than the failure panel.

That card, and a + button beside the map pickers, both open the native
file picker: chosen files are validated before they are let in, copied
under their game's canonical name, and served the same way a hand-
dropped file would be. On Windows a replacement cannot land over an
open archive, so the importer closes the game's archive first and the
rescan that follows reopens the new one.

A stale stamp -- a map asked for just as its bundle changed underneath
the catalog -- now recovers by refetching the catalog and arriving at
the new build's URLs instead of failing the map.

commit

61175aaec4b7c88dc92be5c3265c67a8a1440efd

parent

af61b1a6cf691036c5445d44cee8cafa228e2472

author

Dami <dami.etoile@gmail.com>