Refactor: More state management simplification (#5721)

## Summary

Remove more procedural synchronization in favor of using reactive
references.

> Note: Also includes some fixes for issues caused during HMR.

## Review Focus

In testing it seems to work the same, but let me know if I missed
something.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-5721-Refactor-More-state-management-simplification-2766d73d3650819b8d7ddc047c460f2b)
by [Unito](https://www.unito.io)

tests-ui/tests/renderer/extensions/vueNodes/components/LGraphNode.spec.ts

@@ -50,6 +50,7 @@ vi.mock('@/composables/useErrorHandling', () => ({
 vi.mock('@/renderer/extensions/vueNodes/layout/useNodeLayout', () => ({
   useNodeLayout: () => ({
     position: { x: 100, y: 50 },
+    size: { width: 200, height: 100 },
     startDrag: vi.fn(),
     handleDrag: vi.fn(),
     endDrag: vi.fn()