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/pages/demand/AISearch.tsx

@@ -38,6 +38,7 @@ export default function AISearch() {
   const [weights, setWeights] = useState<Record<WeightingKey, number>>(defaultWeights)
   const [weightingKey, setWeightingKey] = useState(0)
   const [needTitle, setNeedTitle] = useState('')
+  const [isAnonymous, setIsAnonymous] = useState(false)
   const [error, setError] = useState<string | null>(null)
 
   const isManualTextRef = useRef(false)
@@ -165,7 +166,7 @@ export default function AISearch() {
     setStep(NeedBuilderStep.SAVING)
     const entries = Object.entries(parseResult.confidenceByField)
     const conf = entries.length > 0 ? entries.reduce((s, [, v]) => s + v, 0) / entries.length : 0
-    const input = buildNeedInput(editedCriteria, weights, needTitle, conf, 'ACTIVE')
+    const input = buildNeedInput({ ...editedCriteria, isAnonymous: isAnonymous || undefined }, weights, needTitle, conf, 'ACTIVE')
     createNeedMutation.mutate(input, {
       onSuccess: (created) => {
         queryClient.invalidateQueries({ queryKey: ['matches'] })
@@ -253,7 +254,9 @@ export default function AISearch() {
             needTitle={needTitle}
             overallConfidence={overallConfidence}
             isSaving={step === NeedBuilderStep.SAVING}
+            isAnonymous={isAnonymous}
             onNeedTitleChange={setNeedTitle}
+            onAnonymousChange={setIsAnonymous}
             onBack={() => setStep(NeedBuilderStep.IDLE)}
             onSave={handleSaveProfile}
           />