Fix OS switching not working on tree view UI

This commit resolves a rendering bug in the tree view component.
Previously, updating the tree collection prior to node updates led to
rendering errors due to the presence of non-existent nodes in the new
collection.

Changes:

- Implement manual control over the rendering process in tree view. This
  includes clearing the rendering queue and currently rendered nodes
  before updates, aligning the rendering process with the updated
  collection.
- Add Cypress E2E tests to test switching between all operating systems
  and script views, ensuring no uncaught errors and preventing
  regression.
- Replace hardcoded operating system lists in the download URL list view
  with a unified `getSupportedOsList()` method from the application,
  reducing duplication and simplifying future updates.
- Rename `initial-nodes` to `nodes` in `TreeView.vue` to reflect their
  mutable nature.
- Centralize the function for getting operating system names into
  `OperatingSystemNames.ts`, improving reusability in E2E tests.

tests/e2e/code-highlighting.cy.ts

@@ -2,8 +2,8 @@ import { expectExists } from '@tests/shared/Assertions/ExpectExists';
 import { openCard } from './support/interactions/card';
 
 describe('script selection highlighting', () => {
+  // Regression test for a bug where selecting multiple scripts only highlighted the last one.
   it('highlights more when multiple scripts are selected', () => {
-    // Regression test for a bug where selecting multiple scripts only highlighted the last one.
     cy.visit('/');
     selectLastScript();
     getCurrentHighlightRange((lastScriptHighlightRange) => {