feat: responsive layout + Reminder Manager redesign

- Auto-collapse sidebar at <1536px (all laptops), expand at ≥1536px
- Responsive drawer/panel widths across Pipeline, Properties, MyListings, Anfragen, MatchDetail, AISearch
- Reminder Manager: dot+label priority badge, Fläche column removed, status only for non-active rows
- ReminderKpiBar: focal Überfällig card, three secondary KPIs
- ReminderDetailDrawer: Task Panel redesign — Finanzen removed, Notiz promoted, Pre-Market as inline badge, full create form
- useCreateReminder hook wired to reminderService.create with cache invalidation
- Mock data: contract-derived reminders (LEASE_EXPIRY, BREAK_OPTION, RENT_REVIEW, INSURANCE_RENEWAL, SCHATTENMARKT_RELEASE) now show auto-creation note in Verlauf

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

src/hooks/useReminders.ts

@@ -1,5 +1,6 @@
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query'
 import { reminderService } from '../services/reminderService'
+import type { Reminder } from '../domain/reminder'
 import { useToastStore } from '../stores/toastStore'
 
 export function useReminders() {
@@ -69,6 +70,21 @@ export function useSnoozeReminder() {
   })
 }
 
+export function useCreateReminder() {
+  const queryClient = useQueryClient()
+  return useMutation({
+    mutationFn: (data: Omit<Reminder, 'id' | 'activity' | 'createdAt' | 'updatedAt'>) =>
+      reminderService.create(data),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['reminders'] })
+      queryClient.invalidateQueries({ queryKey: ['reminder-insights'] })
+    },
+    onError: () => {
+      useToastStore.getState().showToast('Reminder konnte nicht erstellt werden.', 'error')
+    },
+  })
+}
+
 export function useUpdateReminder() {
   const queryClient = useQueryClient()
   return useMutation({