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/components/match-card/IntelligenceMatchCard.tsx

@@ -399,6 +399,20 @@ export function IntelligenceMatchCard({ vm, imageUrl, lat, lng, cityLabel }: Pro
           {[vm.locationLabel, vm.availabilityLabel].filter(Boolean).join(' · ')}
         </Typography>
 
+        {/* Unit context — only shown when a specific named unit is known */}
+        {vm.preMarketUnit?.unitLabel && (
+          <Box sx={{ display: 'flex', alignItems: 'center', gap: 0.75, mt: 0.5 }}>
+            <Chip
+              size="small"
+              label={`${floorLabel(vm.preMarketUnit.floorLevel)} · ${vm.preMarketUnit.unitLabel}`}
+              sx={{ height: 18, fontSize: '0.62rem', bgcolor: '#f1f5f9', color: '#374151', border: '1px solid #e2e8f0' }}
+            />
+            <Typography variant="caption" sx={{ color: '#64748b', fontSize: '0.68rem' }}>
+              {vm.preMarketUnit.areaSqm.toLocaleString('de-CH')} m²
+            </Typography>
+          </Box>
+        )}
+
         {/* Regular explainability summary */}
         {vm.explainabilitySummary && (
           <>