When controlling a peer renderer, the volume slider must reflect the PEER's
actual volume, never QBZ's local 100, so a drag starts from a safe level and
never nukes the AVR. Extend RemoteNowPlaying with the peer's reported volume
(sourced from the effective remote renderer snapshot) and, in the poll loop's
peer-reflection branch, push it to NowPlayingState.volume as
v/100 (clamped 0..1), falling back to 0.5 (50%) when the peer's volume is
unknown. This branch only runs when a peer is active, so local/renderer
playback is unaffected.
cc
vicrodh
a1b054c387