Improve UI performance by optimizing reactivity

- Replace `ref`s with `shallowRef` when deep reactivity is not needed.
- Replace `readonly`s with `shallowReadonly` where the goal is to only
  prevent `.value` mutation.
- Remove redundant `ref` in `SizeObserver.vue`.
- Remove redundant nested `ref` in `TooltipWrapper.vue`.
- Remove redundant `events` export from `UseCollectionState.ts`.
- Remove redundant `computed` from `UseCollectionState.ts`.
- Remove `timestamp` from `TreeViewFilterEvent` that becomes unnecessary
  after using `shallowRef`.
- Add missing unit tests for `UseTreeViewFilterEvent`.
- Add missing stub for `FilterChangeDetails`.

src/presentation/components/Shared/Icon/UseSvgLoader.ts

@@ -1,5 +1,5 @@
 import {
-  WatchSource, readonly, ref, watch,
+  WatchSource, shallowReadonly, ref, watch,
 } from 'vue';
 import { AsyncLazy } from '@/infrastructure/Threading/AsyncLazy';
 import { IconName } from './IconName';
@@ -15,7 +15,7 @@ export function useSvgLoader(
   }, { immediate: true });
 
   return {
-    svgContent: readonly(svgContent),
+    svgContent: shallowReadonly(svgContent),
   };
 }