Refactor: Consolidate sidebar navigation into 5 top-level sections

Per TODO.md navigation consolidation requirements:
- Home: Dashboard, Notifications
- Teach: Classes, Progress, Assessments, Grading, Reports, Attendance, Homework, Lesson Plans, Resources, Notebooks, Drawing, Portfolio, Rubrics, Comments, Peer Assessment, Tablet Grading, Seating, Subjects, Competitions
- School Life: Calendar, Communication, Announcements, Events, Newsletter, Library, Transport, Counseling, Wellness, Career, Discipline, Behavior, Illness, Substitutes, Timetable, Exam Calendar, Parents
- Insights: Competence Flower, Mastery Matrix, Analytics, Coverage, Grade Analytics, Reports, AI Tests, Data Import/Export
- Administration: Competencies, Districts, Settings

Added i18n keys for new section labels (DE + EN).

src/components/app-layout.tsx

@@ -219,66 +219,78 @@ type NavSection = { id: string; labelKey: string; items: NavItem[] };
 
 const navSections: NavSection[] = [
   {
-    id: 'analysis',
+    id: 'home',
-    labelKey: 'polish.nav_analysis',
+    labelKey: 'polish.nav_home',
     items: [
       { key: 'dashboard', icon: LayoutDashboard, labelKey: 'nav.dashboard' },
-      { key: 'calendar', icon: CalendarIconNav, labelKey: 'nav.calendar' },
+      { key: 'notification-center', icon: Bell, labelKey: 'nav.notification_center' },
-      { key: 'analytics', icon: TrendingUp, labelKey: 'nav.analytics' },
-      { key: 'grade-analytics', icon: BarChart3, labelKey: 'nav.grade-analytics' },
-      { key: 'reports', icon: FileText, labelKey: 'nav.reports' },
-      { key: 'coverage', icon: Target, labelKey: 'nav.coverage' },
     ],
   },
   {
-    id: 'teaching',
+    id: 'teach',
-    labelKey: 'polish.nav_teaching',
+    labelKey: 'polish.nav_teach',
     items: [
       { key: 'classes', icon: Users, labelKey: 'nav.classes' },
       { key: 'progress', icon: PenLine, labelKey: 'nav.progress' },
-      { key: 'flower', icon: Flower2, labelKey: 'nav.flower' },
-      { key: 'matrix', icon: Grid3X3, labelKey: 'nav.matrix' },
       { key: 'assessments', icon: ClipboardCheck, labelKey: 'nav.assessments' },
       { key: 'grading', icon: Calculator, labelKey: 'nav.grading' },
+      { key: 'report-cards', icon: FileText, labelKey: 'nav.report_cards' },
       { key: 'attendance', icon: CalendarCheck, labelKey: 'nav.attendance' },
-      { key: 'lesson-plans', icon: CalendarDays, labelKey: 'nav.lesson_plans' },
-      { key: 'parents', icon: Mail, labelKey: 'nav.parents' },
-      { key: 'behavior', icon: Shield, labelKey: 'nav.behavior' },
       { key: 'homework', icon: BookCheck, labelKey: 'nav.homework' },
-      { key: 'rubrics', icon: Ruler, labelKey: 'nav.rubrics' },
+      { key: 'lesson-plans', icon: CalendarDays, labelKey: 'nav.lesson_plans' },
-      { key: 'comments', icon: MessageSquareText, labelKey: 'nav.comments' },
+      { key: 'resources', icon: LibraryIcon, labelKey: 'nav.resources' },
       { key: 'notebooks', icon: BookOpen, labelKey: 'nav.notebooks' },
       { key: 'drawing', icon: Palette, labelKey: 'nav.drawing' },
       { key: 'portfolio', icon: Briefcase, labelKey: 'nav.portfolio' },
-      { key: 'timetable', icon: ClockIcon, labelKey: 'nav.timetable' },
+      { key: 'rubrics', icon: Ruler, labelKey: 'nav.rubrics' },
-      { key: 'resources', icon: LibraryIcon, labelKey: 'nav.resources' },
+      { key: 'comments', icon: MessageSquareText, labelKey: 'nav.comments' },
-      { key: 'competitions', icon: Trophy, labelKey: 'nav.competitions' },
-      { key: 'subjects', icon: BookOpen, labelKey: 'nav.subjects' },
-      { key: 'illness', icon: Heart, labelKey: 'nav.illness' },
-      { key: 'communication', icon: MessageSquare, labelKey: 'nav.communication' },
-      { key: 'counseling', icon: Heart, labelKey: 'counseling.title' },
-      { key: 'disciplinary', icon: Shield, labelKey: 'disciplinary.title' },
-      { key: 'ai-tests', icon: Brain, labelKey: 'ai_tests.title' },
-      { key: 'tablet-grading', icon: Tablet, labelKey: 'nav.tablet_grading' },
-      { key: 'exam-calendar', icon: CalendarClock, labelKey: 'nav.exam_calendar' },
       { key: 'peer-assessment', icon: UsersRound, labelKey: 'nav.peer-assessment' },
-      { key: 'report-cards', icon: FileText, labelKey: 'nav.report_cards' },
+      { key: 'tablet-grading', icon: Tablet, labelKey: 'nav.tablet_grading' },
       { key: 'seating-chart', icon: LayoutGridIcon, labelKey: 'nav.seating_chart' },
-      { key: 'school-library', icon: LibraryIcon, labelKey: 'nav.school_library' },
+      { key: 'subjects', icon: BookOpen, labelKey: 'nav.subjects' },
-      { key: 'student-wellness', icon: Heart, labelKey: 'nav.student-wellness' },
+      { key: 'competitions', icon: Trophy, labelKey: 'nav.competitions' },
-      { key: 'student-career', icon: Compass, labelKey: 'nav.student-career' },
+    ],
-      { key: 'notification-center', icon: Bell, labelKey: 'nav.notification_center' },
+  },
+  {
+    id: 'school-life',
+    labelKey: 'polish.nav_school_life',
+    items: [
+      { key: 'calendar', icon: CalendarIconNav, labelKey: 'nav.calendar' },
+      { key: 'communication', icon: MessageSquare, labelKey: 'nav.communication' },
       { key: 'announcements', icon: Megaphone, labelKey: 'nav.announcements' },
       { key: 'school-events', icon: PartyPopper, labelKey: 'nav.school-events' },
       { key: 'school-newsletter', icon: Newspaper, labelKey: 'nav.school-newsletter' },
+      { key: 'school-library', icon: LibraryIcon, labelKey: 'nav.school_library' },
       { key: 'school-transport', icon: Bus, labelKey: 'nav.school-transport' },
+      { key: 'counseling', icon: Heart, labelKey: 'counseling.title' },
+      { key: 'student-wellness', icon: Heart, labelKey: 'nav.student-wellness' },
+      { key: 'student-career', icon: Compass, labelKey: 'nav.student-career' },
+      { key: 'disciplinary', icon: Shield, labelKey: 'disciplinary.title' },
+      { key: 'behavior', icon: Shield, labelKey: 'nav.behavior' },
+      { key: 'illness', icon: Heart, labelKey: 'nav.illness' },
       { key: 'substitute-teacher', icon: UserCheck, labelKey: 'nav.substitute-teacher' },
+      { key: 'timetable', icon: ClockIcon, labelKey: 'nav.timetable' },
+      { key: 'exam-calendar', icon: CalendarClock, labelKey: 'nav.exam_calendar' },
+      { key: 'parents', icon: Mail, labelKey: 'nav.parents' },
+    ],
+  },
+  {
+    id: 'insights',
+    labelKey: 'polish.nav_insights',
+    items: [
+      { key: 'flower', icon: Flower2, labelKey: 'nav.flower' },
+      { key: 'matrix', icon: Grid3X3, labelKey: 'nav.matrix' },
+      { key: 'analytics', icon: TrendingUp, labelKey: 'nav.analytics' },
+      { key: 'coverage', icon: Target, labelKey: 'nav.coverage' },
+      { key: 'grade-analytics', icon: BarChart3, labelKey: 'nav.grade-analytics' },
+      { key: 'reports', icon: FileText, labelKey: 'nav.reports' },
+      { key: 'ai-tests', icon: Brain, labelKey: 'ai_tests.title' },
       { key: 'data-import-export', icon: Database, labelKey: 'nav.data-import-export' },
     ],
   },
   {
-    id: 'setup',
+    id: 'administration',
-    labelKey: 'polish.nav_setup',
+    labelKey: 'polish.nav_administration',
     items: [
       { key: 'competencies', icon: BookOpen, labelKey: 'nav.competencies' },
       { key: 'districts', icon: Building2, labelKey: 'nav.districts' },

src/lib/i18n.ts

@@ -813,6 +813,11 @@ const de: TranslationDict = {
   'polish.search_placeholder': 'Schüler, Klassen oder Kompetenzen suchen…',
   'polish.no_results': 'Keine Ergebnisse',
   'polish.help': 'Hilfe',
+  'polish.nav_home': 'Start',
+  'polish.nav_teach': 'Unterricht',
+  'polish.nav_school_life': 'Schulleben',
+  'polish.nav_insights': 'Erkenntnisse',
+  'polish.nav_administration': 'Verwaltung',
   'polish.nav_setup': 'Einrichtung',
   'polish.nav_teaching': 'Unterricht',
   'polish.nav_analysis': 'Analyse',
@@ -7462,6 +7467,11 @@ const en: TranslationDict = {
   'polish.search_placeholder': 'Search students, classes or competencies…',
   'polish.no_results': 'No results',
   'polish.help': 'Help',
+  'polish.nav_home': 'Home',
+  'polish.nav_teach': 'Teach',
+  'polish.nav_school_life': 'School Life',
+  'polish.nav_insights': 'Insights',
+  'polish.nav_administration': 'Administration',
   'polish.nav_setup': 'Setup',
   'polish.nav_teaching': 'Teaching',
   'polish.nav_analysis': 'Analysis',