feat: redesign Schattenmarkt card & detail view for explainability

- Remove abstract Konfidenz/DQ badges from match detail header
- Replace ScoreBreakdownPanel with 3-step Bewertungsherleitung for
  FUTURE_AVAILABILITY: Kriterien-Match per factor with bars, Signal-
  Abschlag (verified ERP = kein Abschlag / probabilistic = -N Punkte),
  Gesamt-Score
- Restructure FutureAvailabilityContextPanel: source section first,
  verified ERP box for LEASE_CONTRACT, remove Konfidenz row, disclaimer
  as grey footnote instead of yellow alert
- Add LEASE_EXPIRY to signal type/relevance bridge labels
- Show up to 3 match reasons with explanation on cards (was 1)
- matchCardAdapter: return top-3 positive factors as reasons

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/features/matching/matchCardAdapter.ts

@@ -15,29 +15,12 @@ import { getCityIntelligence } from '../../lib/locationIntelligence'
 const HARD_CRITERIA = new Set(['area', 'location', 'budget', 'timing'])
 
 function buildReasons(positiveFactors: ScoreFactor[]): MatchCardReason[] {
-  const reasons: MatchCardReason[] = []
-
-  const hardFact = positiveFactors.find(f => HARD_CRITERIA.has(f.criterion))
-  const softFact = positiveFactors.find(f => !HARD_CRITERIA.has(f.criterion))
-
-  if (hardFact) {
-    reasons.push({
-      type: 'HARD_FACT',
-      label: capitalize(hardFact.criterion),
-      explanation: hardFact.explanation,
-      score: hardFact.score,
-    })
-  }
-  if (softFact) {
-    reasons.push({
-      type: 'SOFT_FACTOR',
-      label: capitalize(softFact.criterion),
-      explanation: softFact.explanation,
-      score: softFact.score,
-    })
-  }
-
-  return reasons
+  return positiveFactors.slice(0, 3).map(f => ({
+    type: (HARD_CRITERIA.has(f.criterion) ? 'HARD_FACT' : 'SOFT_FACTOR') as MatchCardReason['type'],
+    label: capitalize(f.criterion),
+    explanation: f.explanation,
+    score: f.score,
+  }))
 }
 
 function capitalize(s: string): string {