fix(nav): register Journal/Planner shapes, fix headerColor crash, enable academic week expansion

Bugs fixed:
- 'cc-teacher-timetable-node' missing from NODE_TYPE_THEMES caused
  Cannot read properties of undefined (reading 'headerColor') crash
  when clicking My Timetable
- 'cc-journal-node' and 'cc-planner-node' had no shape utils registered,
  causing 'No shape util found for type' error on Journal/Planner click
- Added null safety (?? fallback) to getNodeTheme to prevent future crashes
  from any other unmapped type
- Removed AcademicWeek from canExpand exclusion so weeks can be expanded
  to show individual academic days

Added:
- CCJournalNodeShapeUtil and CCPlannerNodeShapeUtil (stub shapes)
- CCJournalNodeProps and CCPlannerNodeProps types
- Journal/Planner added to CCNodeTypes, ccGraphShapeProps, NODE_TYPE_THEMES
- 'cc-department-structure-node' mapping added to NODE_TYPE_THEMES

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

src/utils/tldraw/shapes.ts

@@ -43,6 +43,8 @@ import { CCDepartmentStructureNodeShapeUtil } from './cc-base/cc-graph/CCDepartm
 import { CCUserTeacherTimetableNodeShapeUtil } from './cc-base/cc-graph/CCUserTeacherTimetableNodeShapeUtil'
 import { CCSearchShapeUtil } from './cc-base/cc-search/CCSearchShapeUtil'
 import { CCWebBrowserShapeUtil } from './cc-base/cc-web-browser/CCWebBrowserUtil'
+import { CCJournalNodeShapeUtil } from './cc-base/cc-graph/CCJournalNodeShapeUtil'
+import { CCPlannerNodeShapeUtil } from './cc-base/cc-graph/CCPlannerNodeShapeUtil'
 // Define all shape utils in a single object for easy maintenance
 export const ShapeUtils = {
   CCSlideShow: CCSlideShowShapeUtil,
@@ -89,6 +91,8 @@ export const ShapeUtils = {
   CCUserTeacherTimetableNode: CCUserTeacherTimetableNodeShapeUtil,
   CCSearch: CCSearchShapeUtil,
   CCWebBrowser: CCWebBrowserShapeUtil,
+  CCJournalNode: CCJournalNodeShapeUtil,
+  CCPlannerNode: CCPlannerNodeShapeUtil,
 }
 
 export const allShapeUtils = Object.values(ShapeUtils)