Round 19b: 10 Runtime Bug Fixes, Student Notebook Access, German Curriculum Types

Bug Fixes:
- Fixed duplicate i18n keys (notebooks.type_lined etc.)
- Fixed settings-view.tsx: studentsList undefined → students
- Fixed student-detail-view.tsx: pe.competencyId → pe.competency.id
- Fixed student-detail-view.tsx: locale variable not in scope
- Fixed student-detail-view.tsx: studentId/setStudent undefined
- Fixed notebooks-view.tsx: onClick={onAddPage} passing MouseEvent
- Fixed curriculum-coverage-view.tsx: Map import shadowing built-in
- Fixed api.ts: avatarUrl missing from AttendanceRecord/Report types
- Fixed badge-check.ts: invalid Prisma queries with wrong field names

Student Notebook Access:
- Students can create/view/edit their own notebooks
- Students see shared notebooks from teachers in enrolled classes
- Fixed handleCreateFromTemplate to use correct ownerType for students

German Curriculum Notebook Types (9 types):
- Deutschheft (lined, red), Matheheft (grid, blue), Sachbuch (grid, teal)
- Musikheft (music staff, emerald), Kunstheft (blank, purple)
- Englischheft (lined, amber), Geschichtsheft (lined, brown)
- Religionsheft (lined, orange), Sachkundeheft (lined+drawing, teal)

Environment Features:
- Papier gespart counter with tree calculation
- Eco badge on every notebook card
- Lehrplan-Heft curriculum badge on German types

60+ new i18n keys (DE/EN)

src/lib/api.ts

@@ -582,7 +582,7 @@ export interface Report {
   status: string;
   pdfFilePath: string | null;
   includesGrades: boolean;
-  student: { id: string; firstName: string; lastName: string };
+  student: { id: string; firstName: string; lastName: string; avatarUrl: string | null };
   classGroup: { id: string; name: string; gradeLevel: number };
   schoolYear: { id: string; label: string };
   generatedByUser: { id: string; firstName: string; lastName: string };
@@ -890,7 +890,7 @@ export function downloadCsvExport(params: {
   classGroupId?: string;
   schoolYearId?: string;
   schoolId?: string;
-  format?: 'csv' | 'json';
+  format?: 'csv' | 'json' | 'pdf';
   dateFrom?: string;
   dateTo?: string;
 }): void {
@@ -1141,6 +1141,8 @@ export interface StudentDetailData {
     lastName: string;
     dateOfBirth: string | null;
     externalId: string | null;
+    avatarUrl: string | null;
+    avatarInitials: string | null;
     createdAt: string;
     school: { id: string; name: string };
     enrollments: Array<{
@@ -1548,7 +1550,7 @@ export interface AttendanceRecord {
   status: AttendanceStatus;
   arrivalTime: string | null;
   comment: string | null;
-  student: { id: string; firstName: string; lastName: string };
+  student: { id: string; firstName: string; lastName: string; avatarUrl: string | null };
 }
 
 export interface AttendanceSession {