fix: forward sentiment-adjustment fields in the scores API response

get_score computed base_score / sentiment_score / sentiment_adjustment /
max_sentiment_adjustment, but the router's _map_composite_breakdown built the
response model from only the five original keys and silently dropped the rest — so
the API always returned null for them. That's why the ticker page showed neither the
"Composite = Base + Sentiment" caption nor the ± marker on the sentiment row despite
the frontend and scoring service both supporting it. Pass the fields through, with a
guard test so they can't be dropped again.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/unit/test_scores_router_breakdown.py

@@ -0,0 +1,45 @@
+"""Guard: the scores router must forward the sentiment-adjustment breakdown fields.
+
+get_score computes base_score / sentiment_adjustment, but the router builds the
+response model by hand — so it has to explicitly pass those through, or the ticker
+page loses the "Composite = Base + Sentiment" caption and the ± dimension marker.
+"""
+
+from app.routers.scores import _map_composite_breakdown
+
+
+def test_forwards_sentiment_fields():
+    raw = {
+        "weights": {"technical": 0.25},
+        "available_dimensions": ["technical"],
+        "missing_dimensions": ["sentiment"],
+        "renormalized_weights": {"technical": 1.0},
+        "formula": "x",
+        "base_score": 78.0,
+        "sentiment_score": 75.0,
+        "sentiment_adjustment": 5.0,
+        "max_sentiment_adjustment": 10.0,
+    }
+    model = _map_composite_breakdown(raw)
+    assert model is not None
+    assert model.base_score == 78.0
+    assert model.sentiment_score == 75.0
+    assert model.sentiment_adjustment == 5.0
+    assert model.max_sentiment_adjustment == 10.0
+
+
+def test_none_stays_none():
+    assert _map_composite_breakdown(None) is None
+
+
+def test_old_shaped_dict_defaults_new_fields_to_none():
+    raw = {
+        "weights": {},
+        "available_dimensions": [],
+        "missing_dimensions": [],
+        "renormalized_weights": {},
+        "formula": "x",
+    }
+    model = _map_composite_breakdown(raw)
+    assert model.sentiment_adjustment is None
+    assert model.base_score is None