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`.

tests/unit/shared/Stubs/UseCurrentTreeNodesStub.ts

@@ -1,5 +1,5 @@
 import {
-  WatchSource, readonly, shallowRef, triggerRef,
+  WatchSource, shallowReadonly, shallowRef, triggerRef,
 } from 'vue';
 import { TreeRoot } from '@/presentation/components/Scripts/View/Tree/TreeView/TreeRoot/TreeRoot';
 import { useCurrentTreeNodes } from '@/presentation/components/Scripts/View/Tree/TreeView/UseCurrentTreeNodes';
@@ -25,7 +25,7 @@ export class UseCurrentTreeNodesStub {
     return (treeWatcher: WatchSource<TreeRoot>) => {
       this.treeWatcher = treeWatcher;
       return {
-        nodes: readonly(this.nodes),
+        nodes: shallowReadonly(this.nodes),
       };
     };
   }