Redesign code block controls as a header bar

Language menu becomes a ghost button with a listbox panel, the source
toggle an icon button, and the block one bordered box with a shared
0.75rem left edge.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

C5MAMaggie Appleton and Claude Opus 5.5 authored last monthcommitted by GitHub

8bccad6

Parentf0aa35e

11 files changed+371-51

StackedSplit

apps/web/src/focus.test.ts+10 −2

apps/web/src/tokens.test.ts+0 −7

e2e/code.e2e.ts+11 −5

packages/editor/src/styles.css+95 −12

packages/editor/src/widgets/code-view.tsx+5 −5

packages/editor/src/widgets/code.test.ts+15 −1

packages/editor/src/widgets/code.ts+10 −0

packages/editor/src/widgets/render-blocks.tsx+20 −19

packages/icons/src/index.ts+1 −0

packages/icons/src/line.tsx+9 −0