Two related fixes for abandoned pairings: - After /pair starts a Baileys session, arm a 5-minute timer. If the operator doesn't scan in time the bot stops the session, deletes the pending account row + session files, and pings them in Telegram. - On bot startup, sweep any 'pending' account rows older than 1 hour — catches the case where the bot was restarted mid-pair, leaving a stale row no in-memory state could clean up.