CompetenceTrack v8 - Complete UI/UX redesign, Digital Notebooks, Drawing Canvas, Demo Data Cleanup

Features:
- Complete UI/UX redesign for tablet/stylus optimization
- Digital Notebook system (lined, grid, blank, dotted, music, calligraphy)
- Drawing Canvas with stylus/pen support, pressure sensitivity
- Art class mode with tutorial guides and shape templates
- Demo data one-click cleanup for production transition
- Subject-specific notebook filtering
- Environmental messaging (Papier sparen, Umwelt schützen)
- 44px minimum touch targets for tablet
- No emojis - Lucide icons throughout
- 700+ i18n keys (German/English)
- Notebook types: lined, grid, blank, dotted, music, calligraphy
- Drawing tools: pencil, pen, line, rectangle, circle, eraser
- Undo/redo, color picker, stroke width, export PNG
- Archive/unarchive notebooks
- White backgrounds throughout
- Emerald accent color theme

Backend:
- Notebook CRUD API routes
- Drawing CRUD API routes
- Demo data cleanup API
- Prisma schema with Notebook, NotebookPage, Drawing models
- isDemo flags on all new models

src/app/api/drawings/route.ts

@@ -0,0 +1,96 @@
+import { NextResponse } from 'next/server';
+import { z } from 'zod';
+import { db } from '@/lib/db';
+import { getSession } from '@/lib/auth';
+
+const createDrawingSchema = z.object({
+  title: z.string().min(1).default('Untitled Drawing'),
+  description: z.string().optional(),
+  drawingData: z.string().min(1),
+  imageData: z.string().optional(),
+  schoolId: z.string().optional(),
+  subjectId: z.string().optional(),
+  classGroupId: z.string().optional(),
+  isPublic: z.boolean().default(false),
+});
+
+export async function GET(request: Request) {
+  try {
+    const session = await getSession();
+    if (!session) {
+      return NextResponse.json({ error: 'Not authenticated' }, { status: 401 });
+    }
+
+    const { searchParams } = new URL(request.url);
+    const schoolId = searchParams.get('schoolId') ?? session.user?.schoolId ?? undefined;
+    const subjectId = searchParams.get('subjectId');
+
+    const where: Record<string, unknown> = {};
+    if (schoolId) {
+      where.schoolId = schoolId;
+    }
+    if (subjectId) {
+      where.subjectId = subjectId;
+    }
+
+    // Show own drawings + public drawings from the same school
+    const drawings = await db.drawing.findMany({
+      where: {
+        OR: [
+          { ownerId: session.userId },
+          { isPublic: true, ...(schoolId ? { schoolId } : {}) },
+        ],
+        ...(subjectId ? { subjectId } : {}),
+      },
+      orderBy: { updatedAt: 'desc' },
+    });
+
+    return NextResponse.json(drawings);
+  } catch (error) {
+    console.error('Drawings GET error:', error);
+    return NextResponse.json(
+      { error: 'Internal server error' },
+      { status: 500 }
+    );
+  }
+}
+
+export async function POST(request: Request) {
+  try {
+    const session = await getSession();
+    if (!session) {
+      return NextResponse.json({ error: 'Not authenticated' }, { status: 401 });
+    }
+
+    const body = await request.json();
+    const parsed = createDrawingSchema.safeParse(body);
+    if (!parsed.success) {
+      return NextResponse.json(
+        { error: 'Validation failed', details: parsed.error.issues },
+        { status: 400 }
+      );
+    }
+
+    const drawing = await db.drawing.create({
+      data: {
+        schoolId: parsed.data.schoolId ?? session.user?.schoolId ?? 'default',
+        ownerId: session.userId,
+        title: parsed.data.title,
+        description: parsed.data.description ?? null,
+        drawingData: parsed.data.drawingData,
+        imageData: parsed.data.imageData ?? null,
+        subjectId: parsed.data.subjectId ?? null,
+        classGroupId: parsed.data.classGroupId ?? null,
+        isPublic: parsed.data.isPublic,
+      },
+    });
+
+    return NextResponse.json(drawing, { status: 201 });
+  } catch (error) {
+    console.error('Drawings POST error:', error);
+    return NextResponse.json(
+      { error: 'Internal server error' },
+      { status: 500 }
+    );
+  }
+}