A box whose only external display is an off/standby TV warned "no
external physical display active after the restore (connected=1)" and
forced the EXTEND preset on EVERY teardown — an inert remedy (with one
connected display the preset can't relight anything) that reads like a
fresh failure in every field log.
The backstop now measures its own effect: after a force-EXTEND it
re-reads the inventory, and a dark set that stayed dark THROUGH the
preset is latched as unlightable — subsequent teardowns log a debug line
and leave the topology be. The poisoned-snapshot chain the backstop
exists for is not latched away: there the panel CAN light, so the first
force succeeds and the latch stays clear. Process-lifetime latch, so a
host restart re-probes once.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>