When .restart_last_processed.json goes missing, a redelivered /restart from
Telegram polling can no longer be caught by the update_id comparison, so it
re-restarts the gateway forever (issue #18528, reported by @dontcallmejames
who hit it in production — gateway restarting every ~2min, zero messages
processed).
Fallback: on marker-missing, suppress the /restart only when we can confirm
we just came out of a restart cycle (_booted_from_restart, captured at startup
from .restart_notify.json before it is unlinked) AND the process is still
within a 60s post-boot window. Consumed one-shot. This closes the loop without
swallowing a genuine first /restart on a fresh boot — the flaw in the original
bare-uptime approach.
Credit to @dontcallmejames for the diagnosis and original patch.