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/pipeline/PipelineDetailPanel.tsx

@@ -32,7 +32,7 @@ export function DetailPanel({ item, onClose }: { item: PipelineItem; onClose: ()
 
   return (
     <Box sx={{
-      width: { xs: '100%', md: 340 }, flexShrink: 0,
+      width: { xs: '100%', md: 300, lg: 320, xl: 340 }, flexShrink: 0,
       display: 'flex', flexDirection: 'column',
       bgcolor: 'white', borderLeft: `1px solid ${DS_BORDER.default}`, overflow: 'hidden',
     }}>