feat: sentiment as a signed adjustment to the composite, not averaged in

Going from no sentiment to a bullish read used to be able to *lower* the composite:
sentiment was blended into the weighted average as an absolute level, so a bullish
75 diluted a ticker already scoring 78. That's backwards for a directional signal.

Now the non-sentiment dimensions form a re-normalized weighted-average base, and
sentiment is applied as a signed adjustment around neutral (50):

    composite = clamp(base + MAX_ADJ * (sentiment - 50) / 50)
    MAX_ADJ   = sentiment weight * 100   (default weight 0.10 → ±10)

Neutral leaves the base unchanged, bullish adds and bearish subtracts (scaled by
confidence, since a 50%-confidence call maps to 50 → no effect), and no sentiment
never penalises. Default sentiment weight 0.15 → 0.10; the weight now means "max ±
points." Composite breakdown exposes base_score/sentiment_score/sentiment_adjustment,
and the ScoreCard shows "Base 78 · sentiment +5.0" plus the per-dimension adjustment.

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

frontend/src/components/ui/ScoreCard.tsx

@@ -76,8 +76,14 @@ export function ScoreCard({ compositeScore, dimensions, compositeBreakdown, show
               {compositeScore !== null ? Math.round(compositeScore) : '—'}
             </p>
             {compositeBreakdown && (
-              <p className="mt-1 text-[10px] text-gray-500 leading-snug max-w-[200px]" data-testid="renorm-explanation">
-                Weighted average of available dimensions with re-normalized weights.
+              <p className="mt-1 text-[10px] text-gray-500 leading-snug max-w-[220px]" data-testid="renorm-explanation">
+                {compositeBreakdown.sentiment_adjustment != null &&
+                compositeBreakdown.base_score != null &&
+                Math.abs(compositeBreakdown.sentiment_adjustment) >= 0.05
+                  ? `Base ${Math.round(compositeBreakdown.base_score)} · sentiment ${
+                      compositeBreakdown.sentiment_adjustment >= 0 ? '+' : '−'
+                    }${Math.abs(compositeBreakdown.sentiment_adjustment).toFixed(1)}`
+                  : 'Weighted base of the other dimensions; sentiment adjusts it up or down.'}
               </p>
             )}
           </div>
@@ -107,11 +113,26 @@ export function ScoreCard({ compositeScore, dimensions, compositeBreakdown, show
                     {d.dimension}
                   </span>
                   <div className="flex items-center gap-2">
-                    {weight != null && (
+                    {d.dimension === 'sentiment' && compositeBreakdown?.sentiment_adjustment != null ? (
+                      <span
+                        className={`text-[10px] tabular-nums ${
+                          compositeBreakdown.sentiment_adjustment > 0.05
+                            ? 'text-emerald-400/80'
+                            : compositeBreakdown.sentiment_adjustment < -0.05
+                            ? 'text-red-400/80'
+                            : 'text-gray-500'
+                        }`}
+                        data-testid="weight-sentiment"
+                        title="Points sentiment adds to or subtracts from the base composite"
+                      >
+                        {compositeBreakdown.sentiment_adjustment >= 0 ? '+' : '−'}
+                        {Math.abs(compositeBreakdown.sentiment_adjustment).toFixed(1)}
+                      </span>
+                    ) : weight != null ? (
                       <span className="text-[10px] text-gray-500 tabular-nums" data-testid={`weight-${d.dimension}`}>
                         {Math.round(weight * 100)}%
                       </span>
-                    )}
+                    ) : null}
                     <div className="h-1.5 w-20 rounded-full bg-white/[0.06] overflow-hidden">
                       <div
                         className={`h-1.5 rounded-full bg-gradient-to-r ${barGradient(d.score)} transition-all duration-500`}

frontend/src/lib/types.ts

@@ -82,6 +82,10 @@ export interface CompositeBreakdown {
   missing_dimensions: string[];
   renormalized_weights: Record<string, number>;
   formula: string;
+  base_score?: number | null;
+  sentiment_score?: number | null;
+  sentiment_adjustment?: number | null;
+  max_sentiment_adjustment?: number | null;
 }
 
 export interface ScoreResponse {