feat: Round 24 - Klassenlehrer management, vice principal, exam calendar, student portal exams

- Klassenlehrer management: Assign/change responsible teacher, privilege badges
- Vice principal management: Assign/remove VP role, admins list
- Calendar exam integration: Exam countdown, print calendar, exam filter
- Student portal: Exams tab with countdown, AI study tips, virtual character
- Dashboard: Klassenlehrer section with pending illness/communications
- API: PUT /api/users/role for role management
- API: Enhanced classes GET to include responsibleTeacher
- 90+ new i18n keys

src/components/calendar-view.tsx

@@ -23,6 +23,7 @@ import {
   GraduationCap,
   Filter,
   Timer,
+  Printer,
 } from 'lucide-react';
 import {
   format,
@@ -1116,6 +1117,16 @@ export default function CalendarView() {
             <Filter className="h-4 w-4 mr-1.5" />
             {showExamsOnly ? t('calendar.hide_exams') : t('calendar.show_exams')}
           </Button>
+          {/* Print Calendar button */}
+          <Button
+            variant="outline"
+            size="sm"
+            onClick={() => window.print()}
+            className="border-emerald-200/60 dark:border-emerald-900/30 text-emerald-700 dark:text-emerald-300 hover:bg-emerald-50 dark:hover:bg-emerald-900/20 min-h-[44px]"
+          >
+            <Printer className="h-4 w-4 mr-1.5" />
+            {t('calendar.print')}
+          </Button>
         </div>
       </motion.div>