fix Live Call: don't shutdown shared OkHttp executor on dispose

LiveClient.dispose() called client.dispatcher.executorService.shutdown()
which killed the shared KaizenApi.baseClient dispatcher. After one failed
call, ALL subsequent OkHttp requests (including normal API calls) got
"executor rejected". Removed the shutdown — cancel() on the WS is enough.

app/src/main/java/dev/kaizen/app/live/LiveClient.kt

@@ -115,7 +115,6 @@ class LiveClient(
     fun dispose() {
         active = false
         ws.getAndSet(null)?.cancel()
-        client.dispatcher.executorService.shutdown()
     }
 
     // ─── Reconnect ────────────────────────────────────────────────────────