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/utils/tldraw/cc-base/cc-graph/cc-graph-props.ts

@@ -543,6 +543,8 @@ export const getDefaultCCTimetableLessonNodeProps = () => ({
   start_time: '',
   end_time: '',
   period_code: '',
+  school_db_name: '',
+  school_period_id: '',
 })
 
 export const getDefaultCCPlannedLessonNodeProps = () => ({