feat(ts): R4 TypeScript hardening H1-H6 — reduce errors 177→152

H1: CCGraphNavPanel — useMemo import + LogCategory fix
H2: CCTimetableLessonNodeShapeUtil — props type alignment (cc-graph-props.ts)
H3: cc-graph-shapes — add missing CCTimetableLessonNode* import (was never imported)
H4: CCNodeSnapshotPanel — RestartAlt import from @mui/icons-material
H5: CCExamMarkerPanel + CCFilesPanelEnhanced — BlobPart cast + webkitdirectory @ts-ignore
H6: TranscriptionManager — setTranscriptionCallback interface fix
Plus: CCExportPdfButton BlobPart cast, SimpleUploadTest icon imports, graph-sidebar LogCategory

tsc before: 177 (master)
tsc after:  152 (reduction of 25 errors, well below 160 acceptable threshold)

src/pages/dev/SimpleUploadTest.tsx

@@ -31,6 +31,7 @@ import {
 } from '@mui/material';
 import {
   CloudUpload as UploadIcon,
+  Upload,
   Folder as FolderIcon,
   FolderOpen as FolderOpenIcon,
   Description as FileIcon,
@@ -39,8 +40,12 @@ import {
   PlayArrow as ProcessIcon,
   CheckCircle as SuccessIcon,
   Error as ErrorIcon,
-  Info as InfoIcon
+  Info as InfoIcon,
+  InsertDriveFile,
 } from '@mui/icons-material';
+const FolderOpen = FolderOpenIcon;
+const Refresh = RefreshIcon;
+const Info = InfoIcon;
 import { supabase } from '../../supabaseClient';
 import {
   pickDirectory,

src/pages/tldraw/CCExamMarker/CCExportPdfButton.tsx

@@ -73,8 +73,9 @@ export function CCExportPdfButton({ editor, pdf }: CCExportPdfButtonProps) {
       tickProgress();
     }
 
+    const pdfBytes = await pdf.save();
     const url = URL.createObjectURL(
-      new Blob([await pdf.save()], { type: 'application/pdf' })
+      new Blob([pdfBytes.buffer as ArrayBuffer], { type: 'application/pdf' })
     );
     tickProgress();