Add the Comparison Engine read port, a Core-owned adapter that loads each
timeslot as Work reads it (scoped scanner runs, rolled-up GPO verdicts, backup
creation time only) and GET /projects/:id/timeslot-comparison with validation,
a concurrent-change guard and an off switch. The API client gains an
engine-free getTimeslotComparison and the activity label.
Separate new from regressed scanner deviations and accept a timeslot without
scanner runs on one side. Pair rolled-up GPO Work verdicts by scope and
technical identity with a newer backup set and the same baselines; a changed
value of a still deviating setting stays neutral. compareTimeslots yields the
change categories for the UI and a score delta over comparable sources only.
Move compareScanRuns, comparison normalization and local comparison rules
unchanged to src/evaluation/scan-run-comparison so src/comparison can become
the Comparison Engine; only import paths change. Register the engine paths,
document it in AGENTS.md and onboarding, extend the boundary test and add the
permanent on/off invariance test. Record the decision and staging in the plan.
Binh
Michael
Tronth