finish(STATE-WP-0064): cut over scheduler and split sweep errors from failures

STATE-WP-0064 cutover (state-hub only):
- Retire local custodian-sync.timer; archive units under infra/systemd/archived/
- Mark workplan finished; update infra/README, cron-migration, runbook, AGENTS.md
- Point activity-core-delegation at the consistency-sweep runbook

Consistency engine — automation error vs assessment failure:
- C-00 is an automation error; C-01..C-23 assessment failures are recorded
  for follow-up but no longer fail --remote --all scheduled sweeps (exit 0)
- Skip workplans/README.md in the workplan glob (human index, not a workplan)
- Progress events and compare script expose automation_error and
  assessment_failures separately from exit_code

infra/systemd/archived/custodian-sync.timer

@@ -0,0 +1,11 @@
+[Unit]
+Description=State Hub consistency sync — periodic repo sync (every 15 min)
+Requires=custodian-sync.service
+
+[Timer]
+OnBootSec=5min
+OnUnitActiveSec=15min
+Unit=custodian-sync.service
+
+[Install]
+WantedBy=timers.target