feat(fusion_plating_jobs): auto-pause cron for stale in-progress steps

Plan tasks P2.4 + P2.5 batched.

Adds _cron_autopause_stale_steps method on fp.job.step + 30-min cron
registration. Flips in_progress steps idle > threshold to paused with
a chatter audit ("Auto-paused after Nh idle. Resume from the tablet
when work continues.").

Threshold from ir.config_parameter:
    fp.shopfloor.autopause_threshold_hours  (default 8.0)

Recipe nodes opt out via fusion.plating.process.node.long_running
(added in P2.1) — useful for 24h bakes and multi-shift soaks.

Fixes the 411-hour ghost timer that motivated the redesign. Doesn't
replace the existing nudge crons — those still notify the supervisor;
this one actually pauses the timer.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

fusion_plating/fusion_plating_jobs/tests/__init__.py

@@ -6,3 +6,4 @@ from . import test_display_wo_name
 from . import test_blocker_compute
 from . import test_late_risk_ratio
 from . import test_active_step_id
+from . import test_autopause_cron