reboot command beside poweroff, one polkit grant; forward yukart/gnss/+; mock uses current names

--allow-poweroff becomes --allow-power. deploy/50-yukart-gw-power.pkla adds logind's
reboot actions and the deploy removes the old poweroff-only file.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DDwfd6Ki8UfG4hK6W5YpJz

src/bus.rs

@@ -15,7 +15,7 @@ use std::time::{Duration, Instant};
 use rumqttc::{Client, Event, MqttOptions, Packet, QoS};
 use serde_json::{json, Map, Value};
 
-const TOPICS: [&str; 2] = ["yukart/vehicle/+", "yukart/host/+"];
+const TOPICS: [&str; 3] = ["yukart/vehicle/+", "yukart/host/+", "yukart/gnss/+"];
 const STALE: Duration = Duration::from_secs(5);
 
 struct Entry {