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

@@ -272,6 +272,14 @@ export const ccGraphShapeProps = {
     school_db_name: T.string,
     school_period_id: T.string,
   },
+  'cc-journal-node': {
+    ...graphBaseProps,
+    path: T.string,
+  },
+  'cc-planner-node': {
+    ...graphBaseProps,
+    path: T.string,
+  },
 } as const
 
 // Default props getters
@@ -640,3 +648,17 @@ export const getDefaultCCUserTeacherTimetableNodeProps = () => ({
   school_db_name: '',
   school_timetable_id: '',
 })
+
+export const getDefaultCCJournalNodeProps = () => ({
+  ...getDefaultBaseProps(),
+  title: 'Journal',
+  __primarylabel__: 'Journal',
+  path: '',
+})
+
+export const getDefaultCCPlannerNodeProps = () => ({
+  ...getDefaultBaseProps(),
+  title: 'Planner',
+  __primarylabel__: 'Planner',
+  path: '',
+})