feat(server): pair strangers with quick-match

The hub keeps a FIFO of waiting sessions; a second QuickMatch pops the
first, opens a room via the existing createInput/joinInput path, and
marks it to begin its own first game once both seats are connected in
the lobby. CancelQuickMatch, a dropped connection, and entering a room
by code all remove a session from the queue. Counts queued, cancelled
and matched pairings in metrics.

server/internal/wsapi/codec.go

@@ -79,3 +79,9 @@ func pongMsg(clientTimeMs, serverTimeMs int64) *noituv1.ServerMessage {
 		Pong: &noituv1.Pong{ClientTimeMs: clientTimeMs, ServerTimeMs: serverTimeMs},
 	}}
 }
+
+func quickMatchStatusMsg(queued bool) *noituv1.ServerMessage {
+	return &noituv1.ServerMessage{Payload: &noituv1.ServerMessage_QuickMatchStatus{
+		QuickMatchStatus: &noituv1.QuickMatchStatus{Queued: queued},
+	}}
+}