Use split background reports in promotion gate

docs/TODO.md

@@ -123,6 +123,7 @@ This file now starts with the current implementation status. Older preparation/b
 - [x] Add explicit operator detection profiles for local model assets: balanced review around threshold `0.15` and conservative high-precision review around threshold `0.35`, both clearly marked as non-default-approved until promotion gates pass.
 - [x] Add pure-empty versus sparse-building contextual background corpus classification to operator manifests, hard-negative matrix filters and YOLO tile provenance.
 - [x] Add a split background-corpus matrix runner and report builder that runs pure-empty and sparse-context matrices separately.
+- [x] Teach the model promotion report to consume split background summaries so only `pure_empty_negative` blocks default promotion and `sparse_building_context` stays review-only.
 - [ ] Rerun split background matrices on Tower after rebuild, then retrain or recalibrate against the cleaner pure-empty gate plus separate sparse-context inspection matrix.
 - [ ] Promote a V1 default building detector only after it passes seven positive AOIs, clean hard-negative/background gates and persisted QA/QC evidence without fake detections or model downloads.