feat: F025 button & action logic audit — global toast, confirm dialog, wired mutations

- Add ToastProvider (global MUI Snackbar stack) + toastStore (Zustand)
- Add ConfirmDialog reusable component for destructive actions
- Wire toast feedback to all async mutations: review status, AI output status,
  match approval, shortlist add/remove/title/finalize, signal review actions
- Fix dead UserMenu buttons (Profil, Einstellungen) — show info toast
- Migrate local Snackbar instances in AddToShortlistDialog and
  FutureSignalDetailPanel to global toast store

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

src/pages/supply/MatchCenter.tsx

@@ -13,6 +13,7 @@ import { useMatches, useApproveMatch } from '../../hooks/useMatches'
 import { useProperties } from '../../hooks/useProperties'
 import { useNeeds } from '../../hooks/useNeeds'
 import { useMatchCenterStore } from '../../stores/matchCenterStore'
+import { useToastStore } from '../../stores/toastStore'
 import { MatchListCard, MatchBriefingPanel, MatchCenterSkeleton } from '../../components/match-center'
 import type { Match } from '../../domain/match'
 
@@ -36,6 +37,7 @@ export default function MatchCenter() {
   const { data: needs = [] } = useNeeds()
   const { setSelectedProperty, setSelectedNeed } = useMatchCenterStore()
   const approveMatch = useApproveMatch()
+  const showToast = useToastStore((s) => s.showToast)
 
   const [selectedMatchId, setSelectedMatchId] = useState<string | null>(null)
   const [filterStrength, setFilterStrength] = useState('')
@@ -152,7 +154,10 @@ export default function MatchCenter() {
                 property={propMap.get(match.propertyId)}
                 need={needMap.get(match.needId)}
                 onSelect={() => handleSelectMatch(match)}
-                onApprove={() => approveMatch.mutate(match.id)}
+                onApprove={() => approveMatch.mutate(match.id, {
+                onSuccess: () => showToast('Match genehmigt.'),
+                onError: () => showToast('Genehmigung fehlgeschlagen.', 'error'),
+              })}
               />
             ))}
           </Box>