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/ui/ConfirmDialog.tsx

@@ -0,0 +1,52 @@
+import { Button, Dialog, DialogActions, DialogContent, DialogTitle, Typography } from '@mui/material'
+import { AlertTriangle } from 'lucide-react'
+
+interface Props {
+  open: boolean
+  title: string
+  message: string
+  confirmLabel?: string
+  cancelLabel?: string
+  destructive?: boolean
+  onConfirm: () => void
+  onCancel: () => void
+}
+
+export function ConfirmDialog({
+  open,
+  title,
+  message,
+  confirmLabel = 'Bestätigen',
+  cancelLabel = 'Abbrechen',
+  destructive = false,
+  onConfirm,
+  onCancel,
+}: Props) {
+  return (
+    <Dialog open={open} onClose={onCancel} maxWidth="xs" fullWidth>
+      <DialogTitle sx={{ display: 'flex', alignItems: 'center', gap: 1 }}>
+        {destructive && <AlertTriangle size={18} color="#c0392b" />}
+        {title}
+      </DialogTitle>
+      <DialogContent>
+        <Typography variant="body2" color="text.secondary">
+          {message}
+        </Typography>
+      </DialogContent>
+      <DialogActions sx={{ px: 3, pb: 2 }}>
+        <Button variant="outlined" size="small" onClick={onCancel}>
+          {cancelLabel}
+        </Button>
+        <Button
+          variant="contained"
+          size="small"
+          color={destructive ? 'error' : 'primary'}
+          onClick={onConfirm}
+          autoFocus
+        >
+          {confirmLabel}
+        </Button>
+      </DialogActions>
+    </Dialog>
+  )
+}

src/components/ui/ToastProvider.tsx

@@ -0,0 +1,33 @@
+import { Alert, Snackbar, Stack } from '@mui/material'
+import { useToastStore } from '../../stores/toastStore'
+
+export function ToastProvider() {
+  const { toasts, dismissToast } = useToastStore()
+
+  return (
+    <Stack
+      spacing={1}
+      sx={{ position: 'fixed', bottom: 24, left: '50%', transform: 'translateX(-50%)', zIndex: 9999, alignItems: 'center' }}
+    >
+      {toasts.map((toast) => (
+        <Snackbar
+          key={toast.id}
+          open
+          autoHideDuration={toast.duration ?? 4000}
+          onClose={() => dismissToast(toast.id)}
+          anchorOrigin={{ vertical: 'bottom', horizontal: 'center' }}
+          sx={{ position: 'relative', transform: 'none', left: 'auto', bottom: 'auto' }}
+        >
+          <Alert
+            onClose={() => dismissToast(toast.id)}
+            severity={toast.severity}
+            variant="filled"
+            sx={{ minWidth: 320, boxShadow: 3 }}
+          >
+            {toast.message}
+          </Alert>
+        </Snackbar>
+      ))}
+    </Stack>
+  )
+}

src/components/ui/index.ts

@@ -8,3 +8,5 @@ export { CardSkeleton } from './CardSkeleton'
 export { PanelLoadingState } from './PanelLoadingState'
 export { UnauthorizedState } from './UnauthorizedState'
 export { RestrictedState } from './RestrictedState'
+export { ToastProvider } from './ToastProvider'
+export { ConfirmDialog } from './ConfirmDialog'