jobreg v1.7 - fleet scheduled-job registry, drift-check + heartbeat watchdog

MANIFEST jobreg.tsv (sh.git, same dir) is the SSOT of every timer that SHOULD exist on venus; the tool cross-checks it against systemd's own truth and reports drift both ways (registered-but-dead, live-but-unregistered). OPS-101/OPS-102, Elazar directive via nw-venus-cc 2026-07-12. FINDING FOR THIS EPIC: jobreg itself has NO row in maintainer-agents.sqlite despite being named in KPI-1 and being mine - an instrument the consolidation epic relies on is invisible to the ownership registry. Same drift class as hub-db-backup, which jobreg check caught as UNREGISTERED on 2026-08-22. Registering it is owed.