Round 22: Exam Calendar, Tablet Grading, Student Achievements, Notification Center, Announcements, Styling

- Exam Calendar View: Teacher exam planning with calendar integration
  - Teachers create/modify exams, admin full CRUD, students read-only
  - CalendarEvent integration, 2-week warning, AI test availability badge
  - Monthly/weekly calendar view, list view, statistics

- Tablet Grading View: Stylus annotation and AI grading audit
  - HTML5 Canvas with PointerEvent pressure sensitivity
  - Tool palette: pen, highlighter, eraser, text, stamp
  - Quick grade buttons (German 1-6 scale)
  - AI grading audit with detailed feedback and suggestions

- Student Achievements View: Badges, XP, leaderboard
  - Badge collection grid with category filters
  - Level/XP system with progress bars
  - Leaderboard with opt-in
  - Daily/weekly challenges

- Student Study Planner View: Pomodoro timer, weekly schedule
  - Pomodoro timer with focus score
  - Weekly study schedule with drag-and-drop
  - AI study recommendations
  - Session history and statistics

- Notification Center View: Categories, filters, bulk actions
  - 6 categories, 4 priority levels
  - Real-time polling (10 seconds)
  - Preferences with quiet hours
  - Statistics charts

- School Announcements View: CRUD, read receipts
  - 6 announcement types with gradient headers
  - Pin-to-top, read receipts, target audience
  - Admin/teacher create, students/parents view

- Bug fixes: AnnouncementRead model user relation, User API schoolId field
- i18n: 200+ new keys, breadcrumb navigation fixes
- Styling: Gradient headers, animations, hover effects across all new views

src/app/api/notifications/preferences/route.ts

@@ -0,0 +1,100 @@
+// CompetenceTrack — Notification Preferences API
+import { NextResponse } from 'next/server';
+import { db } from '@/lib/db';
+import { getSession } from '@/lib/auth';
+
+export async function GET() {
+  const session = await getSession();
+  if (!session?.user) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
+  }
+
+  const schoolId = session.user.schoolId;
+  if (!schoolId) {
+    return NextResponse.json({ error: 'No school assigned' }, { status: 400 });
+  }
+
+  let prefs = await db.notificationPreferences.findUnique({
+    where: { userId: session.user.id },
+  });
+
+  // Create default preferences if none exist
+  if (!prefs) {
+    prefs = await db.notificationPreferences.create({
+      data: {
+        userId: session.user.id,
+        schoolId,
+      },
+    });
+  }
+
+  return NextResponse.json(prefs);
+}
+
+export async function PUT(request: Request) {
+  const session = await getSession();
+  if (!session?.user) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
+  }
+
+  const schoolId = session.user.schoolId;
+  if (!schoolId) {
+    return NextResponse.json({ error: 'No school assigned' }, { status: 400 });
+  }
+
+  try {
+    const body = await request.json();
+    const {
+      academicEnabled,
+      behavioralEnabled,
+      administrativeEnabled,
+      calendarEnabled,
+      communicationEnabled,
+      systemEnabled,
+      quietHoursStart,
+      quietHoursEnd,
+      quietHoursEnabled,
+      emailDigestEnabled,
+      emailDigestFrequency,
+    } = body as {
+      academicEnabled?: boolean;
+      behavioralEnabled?: boolean;
+      administrativeEnabled?: boolean;
+      calendarEnabled?: boolean;
+      communicationEnabled?: boolean;
+      systemEnabled?: boolean;
+      quietHoursStart?: string | null;
+      quietHoursEnd?: string | null;
+      quietHoursEnabled?: boolean;
+      emailDigestEnabled?: boolean;
+      emailDigestFrequency?: string;
+    };
+
+    const updateData: Record<string, unknown> = {};
+    if (academicEnabled !== undefined) updateData.academicEnabled = academicEnabled;
+    if (behavioralEnabled !== undefined) updateData.behavioralEnabled = behavioralEnabled;
+    if (administrativeEnabled !== undefined) updateData.administrativeEnabled = administrativeEnabled;
+    if (calendarEnabled !== undefined) updateData.calendarEnabled = calendarEnabled;
+    if (communicationEnabled !== undefined) updateData.communicationEnabled = communicationEnabled;
+    if (systemEnabled !== undefined) updateData.systemEnabled = systemEnabled;
+    if (quietHoursStart !== undefined) updateData.quietHoursStart = quietHoursStart;
+    if (quietHoursEnd !== undefined) updateData.quietHoursEnd = quietHoursEnd;
+    if (quietHoursEnabled !== undefined) updateData.quietHoursEnabled = quietHoursEnabled;
+    if (emailDigestEnabled !== undefined) updateData.emailDigestEnabled = emailDigestEnabled;
+    if (emailDigestFrequency !== undefined) updateData.emailDigestFrequency = emailDigestFrequency;
+
+    const prefs = await db.notificationPreferences.upsert({
+      where: { userId: session.user.id },
+      update: updateData,
+      create: {
+        userId: session.user.id,
+        schoolId,
+        ...updateData,
+      },
+    });
+
+    return NextResponse.json(prefs);
+  } catch {
+    return NextResponse.json({ error: 'Invalid request' }, { status: 400 });
+  }
+}