Two fixes:
1. CLI /stop command crashed with 'cannot import name get_registry' —
the code imported a non-existent function. Fixed to use the actual
process_registry singleton and list_sessions() method.
(Reported in #2458 by haiyuzhong1980)
2. Streaming media delivery used undefined 'adapter' variable —
our PR #2382 called _deliver_media_from_response(adapter=adapter)
but 'adapter' wasn't guaranteed to be defined in that scope.
Fixed to resolve via self.adapters.get(source.platform).
(Reported in #2424 by 42-evey)
f69c47d9ae