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/features/matching/matchCardAdapter.ts

@@ -40,7 +40,9 @@ export function buildMatchCardViewModel(
   const signal = isFuture
     ? (result as FutureAvailabilityResult).signal
     : undefined
-  const unit = isFuture ? (result as FutureAvailabilityResult).unit : undefined
+  const unit = isFuture
+    ? (result as FutureAvailabilityResult).unit
+    : (result as VerifiedPortfolioResult | ExternalMarketResult).unit
 
   const city = property?.location?.city
   const district = property?.location?.district
@@ -121,7 +123,7 @@ export function buildMatchCardViewModel(
     signalUnconfirmedFacts: signal?.unconfirmedFacts,
     signalAreaSqmEstimate: signal?.areaSqmEstimate,
     propertyId: property?.id ?? signal?.propertyId,
-    unitId: unit?.id ?? signal?.unitId,
+    unitId: match.unitId ?? unit?.id ?? signal?.unitId,
     preMarketUnit: unit,
     preMarketAllUnits: property?.units,
   }