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/components/future-signals/FutureSignalDetailPanel.tsx

@@ -1,4 +1,4 @@
-import { Box, Button, Chip, CircularProgress, Divider, IconButton, LinearProgress, Paper, Snackbar, Typography } from '@mui/material'
+import { Box, Button, Chip, CircularProgress, Divider, IconButton, LinearProgress, Paper, Typography } from '@mui/material'
 import { X } from 'lucide-react'
 import { useState } from 'react'
 import { SignalTypeBadge } from './SignalTypeBadge'
@@ -7,6 +7,7 @@ import { SignalReviewStatusBadge } from './SignalReviewStatusBadge'
 import { FutureSignalDisclaimer } from './FutureSignalDisclaimer'
 import { useUpdateSignalReviewStatus } from '../../hooks/useFutureSignals'
 import { useShortlistStore } from '../../stores/shortlistStore'
+import { useToastStore } from '../../stores/toastStore'
 import { reviewService } from '../../services/reviewService'
 import { ReviewStatus } from '../../domain/enums'
 import type { FutureSignal } from '../../domain/futureSignal'
@@ -51,22 +52,37 @@ interface Props {
 export function FutureSignalDetailPanel({ signal, onClose }: Props) {
   const updateStatus = useUpdateSignalReviewStatus()
   const { openAddDialog } = useShortlistStore()
-  const [snackbar, setSnackbar] = useState<string | null>(null)
+  const showToast = useToastStore((s) => s.showToast)
   const [reviewTaskSent, setReviewTaskSent] = useState(false)
 
   const reviewStatus = signal.reviewStatus ?? ReviewStatus.UNREVIEWED
   const isRejected = reviewStatus === ReviewStatus.REJECTED
   const isApproved = reviewStatus === ReviewStatus.APPROVED
 
+  const STATUS_TOAST: Record<string, string> = {
+    IN_REVIEW: 'Signal zur Prüfung markiert.',
+    APPROVED: 'Signal genehmigt.',
+    REJECTED: 'Signal abgelehnt.',
+    FLAGGED: 'Signal markiert.',
+  }
+
   async function handleStatus(status: typeof ReviewStatus[keyof typeof ReviewStatus]) {
-    await updateStatus.mutateAsync({ id: signal.id, status })
-    setSnackbar(`Status aktualisiert: ${status}`)
+    try {
+      await updateStatus.mutateAsync({ id: signal.id, status })
+      showToast(STATUS_TOAST[status] ?? 'Status aktualisiert.')
+    } catch {
+      showToast('Statusänderung fehlgeschlagen.', 'error')
+    }
   }
 
   async function handleSendReview() {
-    await reviewService.createReviewTask(signal.id)
-    setReviewTaskSent(true)
-    setSnackbar('Prüfungsaufgabe erstellt')
+    try {
+      await reviewService.createReviewTask(signal.id)
+      setReviewTaskSent(true)
+      showToast('Prüfungsaufgabe erstellt.')
+    } catch {
+      showToast('Prüfungsaufgabe konnte nicht erstellt werden.', 'error')
+    }
   }
 
   function handleShortlist() {
@@ -242,13 +258,6 @@ export function FutureSignalDetailPanel({ signal, onClose }: Props) {
         </Box>
       </Box>
 
-      <Snackbar
-        open={!!snackbar}
-        autoHideDuration={2500}
-        onClose={() => setSnackbar(null)}
-        message={snackbar}
-        anchorOrigin={{ vertical: 'bottom', horizontal: 'center' }}
-      />
     </Box>
   )
 }