fix FLOAT widget incrementing broken & disabled state styles on widget number input (Vue) (#6036)

## Summary

Align Vue node number widgets with Figma by centralising button styling
and surfacing disabled-state tokens in the design system.

## Changes

- **What**: Added shared
[`useNumberWidgetButtonPt`](src/renderer/extensions/vueNodes/widgets/composables/useNumberWidgetButtonPt.ts)
helper so both PrimeVue `InputNumber` widgets reuse the same Tailwind
token classes, and added the `color/tokens/alpha` values in
[`packages/design-system/src/css/style.css`](packages/design-system/src/css/style.css#L89-L212)
so semantic aliases remain token-driven ([PrimeVue passthrough
docs](https://www.primefaces.org/primevue/passthrough) w
[`color-mix`](https://www.w3.org/TR/css-color-5/#color-mix))

## Review Focus

Confirm hover/active/disabled colours match the design tokens in both
light and dark themes and that float precision still respects the
safe-range guard.

<img width="1377" height="1150" alt="Screenshot from 2025-10-12
17-53-23"
src="https://github.com/user-attachments/assets/c7d34870-5d07-4ce1-9272-7def7ae813b6"
/>

<img width="1377" height="1150" alt="Screenshot from 2025-10-12
17-53-32"
src="https://github.com/user-attachments/assets/86872ec8-979b-4586-879c-41a126a5f932"
/>

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6036-fix-disabled-state-styles-on-Vue-widget-number-input-INT-and-FLOAT-widgets-28b6d73d365081f8aef7fa860b641f7d)
by [Unito](https://www.unito.io)

---------

Co-authored-by: github-actions <[email protected]>

Author: christian-byrne