feat(daemon): publish room member statistics over RPC and the CLI

The statistics parsed from the JoinRoom reply were reachable only from the
library. They answer the question `room users` already exists to ask -- who
is in here, and are they worth downloading from -- so they belong on its
output rather than behind a second call.

- proto: room.member_stats, with a RoomUserStatsDto carrying status, share
  counts, free slots and country
- SessionApi::room_member_stats, so local and remote sessions stay
  interchangeable; the status word is decoded through one shared helper
  rather than a third copy of the match
- `room users` now emits status, average_speed, shared_files,
  shared_folders, slots_free and country, each null when the server said
  nothing, documented in SKILL.md
- docs/openrpc.json regenerated from the wire types

soulseek-rs/src/daemon/proto/mod.rs

@@ -101,6 +101,7 @@ wire_vocabulary! {
         RoomLeave => "room.leave",
         RoomSay => "room.say",
         RoomMembers => "room.members",
+        RoomMemberStats => "room.member_stats",
         MessageSend => "message.send",
         MessageHistory => "message.history",
         BrowseUser => "browse.user",