feat: Schattenmarkt cards — source pills, probability bar, AI summary

Complete IntelligenceMatchCard redesign for FUTURE_AVAILABILITY signals:
purple gradient hero, source type pills, credibility indicators,
probability LinearProgress bar, market indicator badge, AI-generated
signal summary block. Added aiSummary field to FutureSignal domain
and rich German AI summaries to mock signals 001–005.

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

src/domain/futureSignal.ts

@@ -42,4 +42,5 @@ export interface FutureSignal {
   evidence?: SignalEvidence            // structured evidence block
   matchabilityScore?: number           // 0–100: how well this signal can be matched to needs
   reviewStatus?: ReviewStatus
+  aiSummary?: string                   // AI-generated explanation of what this signal means
 }