fix(mission_runtime): seed per-mission gateway with shared pairing state

Fresh mission runtime containers had no ZEROCLAW pairing token so
the topology_worker got 401 Unauthorized on WS connect. Mount the
shared runtimes /root/clawmates-runtime/data as /zeroclaw-data so
the gateway boots pre-paired and accepts the servers ZEROCLAW_TOKEN.

Seed dir overridable via CLAWMATES_RUNTIME_SEED_DIR.

Known caveat: sqlite sessions dir is shared across concurrent
mission runtimes. Fine while topology_worker runs sequentially per
mission; next iteration should copy-on-write per-mission.

frontend/src/components/dashboard/MissionCanvas.tsx

@@ -119,7 +119,6 @@ export function MissionCanvas({
   const [deleteBusy, setDeleteBusy] = useState(false);
   const [runs, setRuns] = useState<MissionRunSummary[]>([]);
   const [lastLoadedAt, setLastLoadedAt] = useState<Date | null>(null);
-  const [refreshClicks, setRefreshClicks] = useState(0);
 
   const load = useCallback(async () => {
     if (!selectedId) {