Cleanup: Remove dead nav items, orphaned i18n keys, and stale ViewName entries
Student Navigation:
- Removed 6 teacher-only items from studentNavSections:
grade-analytics, ai-tests, seating-chart, school-newsletter,
school-transport, substitute-teacher
- Added 9 student-relevant views to studentViews:
counseling, report-cards, student-wellness, student-career,
school-library, announcements, peer-assessment, student-achievements,
student-study-planner
Parent Navigation:
- Removed 2 student-only items from parentNavSections:
student-study-planner, peer-assessment
- Added 8 parent-relevant views to parentViews:
parents, grading, attendance, report-cards, school-library,
student-achievements, student-career, competitions
i18n Cleanup:
- Removed 92 orphaned tablet_grading.* translation keys (47 DE + 45 EN)
These were for features in the deleted tablet-grading-view.tsx component
ViewName Type:
- Removed 'tablet-grading', 'exam-calendar', 'school-events' from ViewName union
(nav entries and renderView cases were already removed in previous commit)