consolidation of some of the modules, localization fixes, product advisories work, qa work

docs/modules/signals/unified-score.md

@@ -2,7 +2,7 @@
 
 > **Ownership:** Signals Guild / Platform Guild
 > **Services:** `StellaOps.Signals.UnifiedScore`
-> **API:** `POST /api/v1/score/evaluate`, `GET /api/v1/score/{id}/replay`
+> **API:** `POST /api/v1/score/evaluate`, `GET /api/v1/score/{id}/replay`, `GET /api/v1/score/explain/{digest}`
 > **CLI:** `stella score compute|explain|replay|verify`, `stella gate score evaluate`
 
 ## Overview
@@ -92,6 +92,15 @@ See [Scoring Algebra §4](../../technical/scoring-algebra.md) for the manifest s
 | `GET` | `/api/v1/score/weights/effective` | Get effective manifest for a date |
 | `GET` | `/api/v1/score/{scoreId}/replay` | Fetch signed replay proof |
 | `POST` | `/api/v1/score/verify` | Verify a replay log |
+| `GET` | `/api/v1/score/explain/{digest}` | Fetch canonical explanation contract (`score.explain.v1`) |
+
+### Explain Error Taxonomy
+
+`GET /api/v1/score/explain/{digest}` uses deterministic error bodies:
+
+- `400` + `code=invalid_input`
+- `404` + `code=not_found`
+- `503` + `code=backend_unavailable`
 
 ### Evaluate Request
 
@@ -124,6 +133,8 @@ See [Scoring Algebra §4](../../technical/scoring-algebra.md) for the manifest s
   "bucket": "ScheduleNext",
   "unknowns_fraction": 0.15,
   "unknowns_band": "Complete",
+  "unknowns": ["runtime", "backport"],
+  "proof_ref": "proof://score/sha256%3A...",
   "weight_manifest": {
     "version": "v2026-01-22",
     "content_hash": "sha256:..."