fix: five dashboard improvements across booking, vehicles, profile, and UI

- fix(auth): guard extractNames() against Authentik sending full name in
  given_name field (e.g. "Matthias Hochmeister" + family_name "Hochmeister");
  detect by checking given_name ends with family_name suffix, fall through
  to name-splitting so Vorname/Nachname display correctly in Profile

- fix(db): add migration 018 to repair broken BEFORE UPDATE triggers on
  veranstaltungen and veranstaltung_kategorien; old triggers called
  update_updated_at_column() which references NEW.updated_at, but both
  tables use aktualisiert_am, causing every category/event edit to fail

- feat(booking): open vehicle booking creation to all authenticated users;
  only dashboard_admin / dashboard_moderator can change the Buchungsart
  (type select disabled for regular members); edit and cancel still
  restricted to WRITE_GROUPS

- feat(vehicles): VehicleDashboardCard now fetches equipment warnings via
  equipmentApi.getVehicleWarnings() in parallel and shows an alert when
  any vehicle equipment is not einsatzbereit

- fix(ui): add MuiTextField defaultProps (InputLabelProps.shrink=true) and
  MuiOutlinedInput notch legend font-size override to theme to eliminate
  floating-label / border conflict on click

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

frontend/src/components/vehicles/VehicleDashboardCard.tsx

@@ -11,7 +11,9 @@ import {
 } from '@mui/material';
 import { Link as RouterLink } from 'react-router-dom';
 import { vehiclesApi } from '../../services/vehicles';
+import { equipmentApi } from '../../services/equipment';
 import type { VehicleStats, InspectionAlert } from '../../types/vehicle.types';
+import type { VehicleEquipmentWarning } from '../../types/equipment.types';
 
 interface VehicleDashboardCardProps {
   hideWhenEmpty?: boolean;
@@ -22,6 +24,7 @@ const VehicleDashboardCard: React.FC<VehicleDashboardCardProps> = ({
 }) => {
   const [stats, setStats] = useState<VehicleStats | null>(null);
   const [alerts, setAlerts] = useState<InspectionAlert[]>([]);
+  const [equipmentWarnings, setEquipmentWarnings] = useState<VehicleEquipmentWarning[]>([]);
   const [loading, setLoading] = useState(true);
   const [error, setError] = useState<string | null>(null);
 
@@ -31,13 +34,15 @@ const VehicleDashboardCard: React.FC<VehicleDashboardCardProps> = ({
       try {
         setLoading(true);
         setError(null);
-        const [statsData, alertsData] = await Promise.all([
+        const [statsData, alertsData, warningsData] = await Promise.all([
           vehiclesApi.getStats(),
           vehiclesApi.getAlerts(30),
+          equipmentApi.getVehicleWarnings(),
         ]);
         if (mounted) {
           setStats(statsData);
           setAlerts(alertsData);
+          setEquipmentWarnings(warningsData);
         }
       } catch {
         if (mounted) setError('Fahrzeugstatus konnte nicht geladen werden.');
@@ -84,7 +89,8 @@ const VehicleDashboardCard: React.FC<VehicleDashboardCardProps> = ({
   const hasConcerns =
     overdueAlerts.length > 0 ||
     upcomingAlerts.length > 0 ||
-    stats.ausserDienst > 0;
+    stats.ausserDienst > 0 ||
+    equipmentWarnings.length > 0;
 
   const allGood = stats.einsatzbereit === stats.total && !hasConcerns;
 
@@ -133,6 +139,14 @@ const VehicleDashboardCard: React.FC<VehicleDashboardCardProps> = ({
                 </Typography>
               </Alert>
             )}
+            {equipmentWarnings.length > 0 && (
+              <Alert severity="warning" variant="outlined" sx={{ py: 0.5 }}>
+                <AlertTitle sx={{ fontWeight: 600, mb: 0.5 }}>Ausrüstung nicht verfügbar</AlertTitle>
+                <Typography variant="body2">
+                  {equipmentWarnings.length} Ausrüstungsgegenstand{equipmentWarnings.length !== 1 ? 'stände' : 'stand'} nicht einsatzbereit
+                </Typography>
+              </Alert>
+            )}
           </Box>
         )}