feat: unit-level matching architecture — match against Einheiten, not Objekte

- domain/property: add getEffectiveUnits() — returns explicit units or synthesises
  one from property-level data so all properties work uniformly at unit level
- domain/match: add unitId? field — every Match references a specific unit
- domain/unifiedResult: add unit? to VerifiedPortfolioResult + ExternalMarketResult
- MockupNeedProvider: generateSyntheticMatches iterates getEffectiveUnits(prop);
  computeScore uses unit-level areaSqm + rentPricePerSqm; resultId for PRE-MARKET
  signals matches useSchattenmarktSignals signal ID format
- useUnifiedResults: resolve unit from match.unitId for VERIFIED_PORTFOLIO/EXTERNAL_MARKET
- matchCardAdapter: unit now extracted for all result types; unitId from match.unitId
- IntelligenceMatchCard: regular cards show unit chip (floor + label + m²) when a
  named unit is known — only adds context, never shows for synthetic/whole-property units

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

src/domain/unifiedResult.ts

@@ -18,12 +18,14 @@ export interface VerifiedPortfolioResult extends UnifiedResultBase {
   resultType: 'VERIFIED_PORTFOLIO'
   property: Property
   match: Match
+  unit?: PropertyUnit    // specific unit this match refers to
 }
 
 export interface ExternalMarketResult extends UnifiedResultBase {
   resultType: 'EXTERNAL_MARKET' | 'MAISON_WORK'
   property: Property
   match: Match
+  unit?: PropertyUnit    // specific unit this match refers to
 }
 
 export interface FutureAvailabilityResult extends UnifiedResultBase {