Automations UI refinements (#28190)

ref https://linear.app/ghost/issue/NY-1312/minor-ui-refinements

## What changed

- Refined the automations list into a more compact settings-list
treatment by removing the desktop-only table header, adding a top
border, tightening the skeleton rows, and right-aligning the LIVE/OFF
status column.
- Updated the automation canvas with a light grey dotted React Flow
background, darker dot pattern, and subtler sidebar shadow treatment.
- Adjusted automation step cards so selected cards keep the darker
selected outline while hover borders only apply to unselected cards.
- Polished editor controls by switching the add-step edge/button
treatment from blue to green.
- Tweaked the automation editor header typography, icon-button sizing,
menu width, and wait input height.

## Why

These are beta UI refinements for Automations. The goal is to make the
list easier to scan, make the canvas feel more intentionally designed,
and keep editor controls visually consistent with the action treatment.