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/components/layout/AppShell.tsx

@@ -21,16 +21,21 @@ export function AppShell() {
   const sidebarCollapsed = useLayoutStore(s => s.sidebarCollapsed)
   const setActiveWorkspace = useLayoutStore(s => s.setActiveWorkspace)
   const toggleSidebar = useLayoutStore(s => s.toggleSidebar)
+  const setSidebarCollapsed = useLayoutStore(s => s.setSidebarCollapsed)
   const { currentUser } = useSessionStore()
   const navigate = useNavigate()
   const location = useLocation()
   const theme = useTheme()
-  const isMobile = useMediaQuery(theme.breakpoints.down('md'))
+  const isMobile = useMediaQuery(theme.breakpoints.down('sm'))
+  const isCompact = useMediaQuery(theme.breakpoints.down('xl'))
   const [mobileOpen, setMobileOpen] = useState(false)
 
   // Close mobile menu on route change
   useEffect(() => { setMobileOpen(false) }, [location.pathname])
 
+  // Auto-collapse sidebar on compact screens (laptops < 1536px)
+  useEffect(() => { setSidebarCollapsed(isCompact) }, [isCompact, setSidebarCollapsed])
+
   // Sync active workspace with URL
   useEffect(() => {
     const detected = getWorkspaceFromPath(location.pathname)