feat(exam): Assessment dashboard + /exam-marker route; remove old CCExamMarker (S4-8)

- New examRepository (R2.1 seam): the only module talking to /api/exam (Supabase
  JWT → Bearer, axios to API_BASE). list/get/create/archive templates.
- ExamDashboardPage (/exam-marker): lists institute templates, create dialog,
  archive; cards link to setup (S4-9). Wrapped in ErrorBoundary (R6.4).
- exam.types.ts mirrors the API contract.
- Dashboard 'Exam Marker' quick action (top-level discovery, R1.3/R6.1).
  Note: the in-canvas TeacherNavigation is unsuitable for a nav section (it's
  the worker prev/next tab bar) — flagged; used the dashboard entry instead.
- R1.1 removal: deleted src/pages/tldraw/CCExamMarker/ (old 3-PDF viewer) and
  the now-dead CCExamMarkerPanel + its wiring in CCPanel/BasePanel (examMarkerProps
  was only ever passed by the deleted page).
- Fixed pre-existing broken AppRoutes test (missing TimetableListPage mock export).

Build green (vite); AppRoutes route tests pass; typecheck clean for new files.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

src/utils/tldraw/ui-overrides/components/shared/BasePanel.tsx

@@ -1,5 +1,4 @@
 import React, { useEffect, useRef, useMemo, useState } from 'react';
-import { useLocation } from 'react-router-dom';
 import { TldrawUiButton } from '@tldraw/tldraw';
 import { CCShapesPanel } from './CCShapesPanel';
 import { CCSlidesPanel } from './CCSlidesPanel';
@@ -7,7 +6,6 @@ import { CCFilesPanel } from './CCFilesPanel';
 import { CCCabinetsPanel } from './CCCabinetsPanel';
 import { CCYoutubePanel } from './CCYoutubePanel';
 import { CCGraphPanel } from './CCGraphPanel';
-import { CCExamMarkerPanel } from './CCExamMarkerPanel';
 import { CCSearchPanel } from './CCSearchPanel';
 import { CCGraphNavPanel } from './navigation/CCGraphNavPanel';
 import { CCTranscriptionPanel } from './CCTranscriptionPanel';
@@ -31,16 +29,12 @@ export const PANEL_TYPES = {
     { id: 'graph', label: 'Graph', order: 60 },
     { id: 'search', label: 'Search', order: 70 },
   ],
-  examMarker: [
-    { id: 'exam-marker', label: 'Exam Marker', order: 10 },
-  ],
 } as const;
 
-export type PanelType = typeof PANEL_TYPES.default[number]['id'] | typeof PANEL_TYPES.examMarker[number]['id'];
+export type PanelType = typeof PANEL_TYPES.default[number]['id'];
 
 interface BasePanelProps {
   initialPanelType?: PanelType;
-  examMarkerProps?: React.ComponentProps<typeof CCExamMarkerPanel>;
   isExpanded?: boolean;
   isPinned?: boolean;
   onExpandedChange?: (expanded: boolean) => void;
@@ -125,16 +119,6 @@ function getIconSvg(panelId: PanelType, size = '1.25rem') {
           <path d="M19 21l-7-5-7 5V5a2 2 0 0 1 2-2h10a2 2 0 0 1 2 2z" />
         </svg>
       );
-    case 'exam-marker':
-      return (
-        <svg {...common}>
-          <path d="M14 2H6a2 2 0 0 0-2 2v16a2 2 0 0 0 2 2h12a2 2 0 0 0 2-2V8z" />
-          <polyline points="14 2 14 8 20 8" />
-          <line x1="16" y1="13" x2="8" y2="13" />
-          <line x1="16" y1="17" x2="8" y2="17" />
-          <polyline points="10 9 9 9 8 9" />
-        </svg>
-      );
     default:
       return (
         <svg {...common}>
@@ -152,7 +136,6 @@ function isDarkMode() {
 
 export const BasePanel: React.FC<BasePanelProps> = ({
   initialPanelType = 'files',
-  examMarkerProps,
   isExpanded: controlledIsExpanded,
   isPinned: controlledIsPinned,
   onExpandedChange,
@@ -160,7 +143,6 @@ export const BasePanel: React.FC<BasePanelProps> = ({
   isMenuOpen = false,
   onMenuOpenChange = () => {},
 }) => {
-  const location = useLocation();
   const { tldrawPreferences } = useTLDraw();
   const [prefersDarkMode, setPrefersDarkMode] = useState(isDarkMode());
   const [menuOpen, setMenuOpen] = useState(false);
@@ -177,12 +159,9 @@ export const BasePanel: React.FC<BasePanelProps> = ({
     ? 'dark'
     : 'light';
 
-  const isExamMarkerRoute = location.pathname === '/exam-marker';
-  const availablePanels = isExamMarkerRoute ? PANEL_TYPES.examMarker : PANEL_TYPES.default;
+  const availablePanels = PANEL_TYPES.default;
 
-  const [currentPanelType, setCurrentPanelType] = useState<PanelType>(
-    isExamMarkerRoute ? 'exam-marker' : initialPanelType
-  );
+  const [currentPanelType, setCurrentPanelType] = useState<PanelType>(initialPanelType);
 
   const [internalIsExpanded, setInternalIsExpanded] = useState(true);
   const [internalIsPinned, setInternalIsPinned] = useState(true);
@@ -223,10 +202,6 @@ export const BasePanel: React.FC<BasePanelProps> = ({
   }, [isExpanded, isPinned]);
 
   const renderCurrentPanel = () => {
-    if (isExamMarkerRoute && currentPanelType === 'exam-marker') {
-      return examMarkerProps ? <CCExamMarkerPanel {...examMarkerProps} /> : null;
-    }
-
     switch (currentPanelType) {
       case 'cabinets':
         return <CCCabinetsPanel />;
@@ -331,7 +306,6 @@ export const BasePanel: React.FC<BasePanelProps> = ({
                           {type.id === 'search' && 'Search through your content'}
                           {type.id === 'navigation' && 'Navigate through different contexts'}
                           {type.id === 'node-snapshot' && 'Manage node snapshots'}
-                          {type.id === 'exam-marker' && 'Mark and grade exams'}
                         </span>
                       </span>
                     </button>