[Foundation] Finalise density naming and values

[millus]

Two related loose ends from PR #4660 that are both blocked on Token Studio being configured with the correct density values from Figma.

1. Density naming rename

The current data-density values need to be renamed to align with Figma:

Current	Renamed
relaxed	spacious
spacious	comfortable
comfortable	compact

This is a breaking change for any consumers already using data-density, so it should be coordinated with the Figma side before shipping.

2. relaxed-density.css real values

relaxed-density.css is currently a POC with placeholder values. Once the correct density scale is defined in Token Studio and synced, replace the placeholders with the real token values.

Blocked on

Token Studio needs to be configured with the density scale from Figma before either of these can be finalised.

Related

• PR feat(eds-core-react): create button label typography css #4660 — Button label typography CSS (where both TODOs were introduced)

[millus]

The density rename (relaxed → spacious → comfortable → compact) is tracked as part of #4743. The code-side changes in this issue can be picked up once the token work in #4743 is done.