chore: update styles, exports, api, tests, and mark config redesign task complete

- configStyles.ts: add listDetailRoot, listPane, listItem, listItemSelected,
  detailPane style slots
- index.ts: export ConfigListDetail and RawConfigSection
- api/config.ts: add writeFilterFile and writeActionFile API helpers
- setupTests.ts: add ResizeObserver and matchMedia mocks for Fluent UI v9
- ConfigPageLogPath.test.tsx: update to render inside FluentProvider
- Docs/Tasks.md: mark config view redesign task as complete

frontend/src/setupTests.ts

@@ -17,6 +17,9 @@ class ResizeObserverStub {
 
 globalThis.ResizeObserver = ResizeObserverStub;
 
+// jsdom does not implement scrollIntoView.
+Element.prototype.scrollIntoView = () => {};
+
 // Fluent UI animations rely on matchMedia.
 Object.defineProperty(window, "matchMedia", {
   writable: true,