fix(Input): number spin buttons, ID generation, layout shift & a11y

[stayzappy]

Description

This PR resolves the requested issues regarding the Input component's behavior and layout stability, while also layering in missing accessibility properties for the error/hint layout.

Changes Made:

• Number Spin Buttons: Verified CSS rule added in index.css successfully overrides browser -webkit-appearance and -moz-appearance styles.
• ID Generation: Verified useId() correctly supplies a stable ID to the input element when id and label are absent.
• Layout Shifts: Verified the container utilizes min-h-[18px] to ensure no CLS penalties or layout shifts occur when the error state toggles the hint visibility.
• Accessibility Enhancements: Added aria-describedby and aria-invalid to explicitly link the input to its respective error and hint <p> tags for screen readers.

(Note: The primary CSS and layout shift changes were already present in main, so this PR specifically supplements the existing fixes with standard ARIA mappings to ensure robust a11y).

Closes #123