fix: property-level scoring for multi-unit properties + multi-unit chip

For properties with explicit sub-units (e.g. prop-001: 280/310/260 m²),
synthetic matching now generates ONE property-level match using the aggregate
areaSqm (850 m²) instead of per-unit matches — ensuring a need for 800-1000 m²
correctly scores the whole floor as +20 (STRONG) rather than -10 each unit.

Pre-market unit-level matches are still generated per released unit so tenants
seeking smaller spaces still see the specific unit signals.

Card shows "X Einheiten · total Y m²" chip when a multi-unit property is matched
at property level (no specific unit assigned).

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

src/components/match-card/IntelligenceMatchCard.tsx

@@ -399,7 +399,7 @@ 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 */}
+        {/* Specific named unit */}
         {vm.preMarketUnit?.unitLabel && (
           <Box sx={{ display: 'flex', alignItems: 'center', gap: 0.75, mt: 0.5 }}>
             <Chip
@@ -413,6 +413,20 @@ export function IntelligenceMatchCard({ vm, imageUrl, lat, lng, cityLabel }: Pro
           </Box>
         )}
 
+        {/* Multi-unit property: no specific unit matched — show aggregate summary */}
+        {!vm.preMarketUnit && (vm.preMarketAllUnits?.length ?? 0) > 1 && (
+          <Box sx={{ display: 'flex', alignItems: 'center', gap: 0.75, mt: 0.5 }}>
+            <Chip
+              size="small"
+              label={`${vm.preMarketAllUnits!.length} Einheiten`}
+              sx={{ height: 18, fontSize: '0.62rem', bgcolor: '#eff6ff', color: '#1e40af', border: '1px solid #bfdbfe' }}
+            />
+            <Typography variant="caption" sx={{ color: '#64748b', fontSize: '0.68rem' }}>
+              total {vm.preMarketAllUnits!.reduce((s, u) => s + u.areaSqm, 0).toLocaleString('de-CH')} m²
+            </Typography>
+          </Box>
+        )}
+
         {/* Regular explainability summary */}
         {vm.explainabilitySummary && (
           <>