feat(KB-048): add collapsible list sections to dashboard

- Add section expansion state management with localStorage persistence
- Update section headers with chevron toggle controls
- Implement conditional task row rendering based on section state
- Add Expand All / Collapse All toolbar controls
- Add CSS styles for chevron rotation animation and section headers
- Add comprehensive tests for collapsible section behavior

packages/dashboard/app/components/__tests__/Column.test.tsx

@@ -25,10 +25,12 @@ function makeTask(id: string): Task {
     column: "triage" as ColumnType,
     status: undefined as any,
     steps: [],
+    currentStep: 0,
     dependencies: [],
     description: "",
-    created: new Date().toISOString(),
-    updated: new Date().toISOString(),
+    log: [],
+    createdAt: new Date().toISOString(),
+    updatedAt: new Date().toISOString(),
   };
 }