Segment Sense: set priority 5, disable 5 absorbed agents
Sense runs first (P5) before all other segment agents. Disable agents
absorbed by the Sense + state machine architecture: activity, speakers,
facets, activity_state, activities. Preserved via frontmatter flag (not
deleted) per spec — can be re-enabled if needed.
Part of segment-sense mainline implementation (req_k234bcfs).