Two bugs found during live verification on the server:
1. Stuck state after external restart: if something else restarted xmrig
(e.g. deploy-rs activation) while paused_by_us=True, the script never
detected this and became permanently stuck — unable to stop xmrig on
future load because it thought xmrig was already stopped.
Fix: when paused_by_us=True and busy, check if xmrig is actually
running. If so, reset paused_by_us=False and re-stop it.
2. Flapping on xmrig restart: RandomX dataset init takes ~3.7s of intense
non-nice CPU, which the script detected as real workload and immediately
re-stopped xmrig after every restart, creating a start-stop loop.
Fix: add STARTUP_COOLDOWN (default 10s) — after starting xmrig, skip
CPU checks until the cooldown expires.
Both bugs were present in production: the script had been stuck since
Apr 3 (2+ days) with xmrig running unmanaged alongside llama-server.
