FeathersNumberInput remaining work

The `FeathersNumberInput` widget is not yet complete:

* The widget should have increment and decrement arrows at each end, using the standard chevron icons. These should only appear when all of the following are true:
* The widget has no SoftLimit (because otherwise it appears as a slider)
* The widget is being hovered
* The widget currently lacks AccessibilityNode role and attributes for range value input.

Find the FeathersNumberInput implementation and inspect how SoftLimit, hover state, chevron icons, and AccessibilityNode attributes are handled. Confirm the arrows appear only for hovered widgets without SoftLimit, and verify that range-value accessibility role and attributes are present.

Written by the indexing model from the issue text.