feat: anonymes Suchprofil — Toggle im Speichern-Schritt, supply-side Masking

- Toggle 'Anonymes Suchprofil' im AISearchSavePreview (nicht in Suchmaske)
- Box wechselt zu lila wenn aktiv, Text erklärt was anonymisiert wird
- isAnonymous wird via buildNeedInput in gespeichertes Need geschrieben
- MatchListCard + NeedSelectionPanel: zeigen 'Anonyme Anfrage' (lila) statt Firmenname

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

src/components/match-center/MatchListCard.tsx

@@ -70,9 +70,12 @@ export function MatchListCard({ match, property, need, onSelect, onApprove }: Pr
         <Box sx={{ display: 'flex', gap: 0.75, mt: 0.5, flexWrap: 'wrap' }}>
           {need && (
             <Chip
-              label={need.companyName}
+              label={need.isAnonymous ? 'Anonyme Anfrage' : need.companyName}
               size="small"
-              sx={{ bgcolor: '#eff6ff', color: '#1e3a5f', fontSize: 11, height: 20, fontWeight: 500 }}
+              sx={need.isAnonymous
+                ? { bgcolor: '#f5f3ff', color: '#6d28d9', fontSize: 11, height: 20, fontWeight: 600, border: '1px solid #ddd6fe' }
+                : { bgcolor: '#eff6ff', color: '#1e3a5f', fontSize: 11, height: 20, fontWeight: 500 }
+              }
             />
           )}
           <Chip