feat: Objekt→Einheit architecture — unit-level pre-market, property detail page, click-through from cards

- Domain: PropertyUnit extended with propertyId + schattenmarktRelease per unit
- Domain: FutureAvailabilityResult carries resolved property + unit
- useSchattenmarktSignals: generates unit-level signals (schattenmarkt-{propId}-{unitId})
- useUnifiedResults: resolves backing property + unit on FUTURE_AVAILABILITY fast path
- IUnitProvider + MockupUnitProvider: first-class unit access and mutation
- matchCardAdapter: maps preMarketUnit, preMarketAllUnits, propertyId, unitId to ViewModel
- IntelligenceMatchCard: PRE-MARKET VERIFIED shows unit info strip + "Zur Einheit →" button
- PropertyDetailView: unit-level toggles + date pickers inside PreMarketPanel
- New page: /demand/property/:propertyId with unit table, status chips, inquiry form
- App.tsx: demand route /demand/property/:propertyId registered
- Mock data: prop-001/007/037 units updated with correct lease dates + unit-level schattenmarktRelease

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

src/components/match-card/MatchCardViewModel.ts

@@ -1,5 +1,6 @@
 import type { ResultType } from '../../domain/enums'
 import type { TradeOff, Risk, MissingDataItem } from '../../domain/match'
+import type { PropertyUnit } from '../../domain/property'
 
 export type MatchCardVariant = 'compact' | 'expanded' | 'review' | 'compare-mini'
 
@@ -66,6 +67,12 @@ export interface MatchCardViewModel {
   signalIsControlled?: boolean
   signalAreaSqmEstimate?: number
 
+  // Property / unit reference (for FUTURE_AVAILABILITY with a backing property)
+  propertyId?: string
+  unitId?: string
+  preMarketUnit?: PropertyUnit   // specific unit being released pre-market
+  preMarketAllUnits?: PropertyUnit[] // all units of the backing property
+
   // States
   isSelected?: boolean
   isCompareSelected?: boolean