A refrakt-side codemod that rewrites authored elevation="none|sm|md|lg" in content to the new values (none→flat, sm/md→raised, lg→floating); run it across the site. Scope it to the elevation attribute only — frame-shadow carries the identical none/sm/md/lg values and must not be touched (SPEC-107 §1).
Rewrite surfaces.md (the canonical surfaces reference) around the three axes — including the two-layer model (surface axes elevation/prominence vs the layout axis width) and the elevation ↔ frame-shadow boundary; migrate the elevation= usages in figure.md, card.md, bento.md; update extend/theme-authoring/dimensions (and any reference to the old named scale).
Add a changeset documenting the breaking change + the alias deprecation window. Leave releases.md (historical) untouched.

Acceptance Criteria

A codemod migrates elevation values in content; the site has no remaining none|sm|md|lg elevation usages. Authored frame-shadow="none|sm|md|lg" is left untouched.
surfaces.md documents elevation (ladder), width (bleed), and prominence (family) accurately; figure/card/bento examples use the new values.
A changeset records the breaking change and the deprecation window.

Dependencies

Requires WORK-423 (aliases to migrate from) and WORK-425 (final vocabulary in the theme).

SPEC-107 · site/content/runes/surfaces.md · site/content/extend/theme-authoring/dimensions.md.