The feed's head is named in docs/design/areas/feed.md, and .feed-head leaves §5d #5503

For: the head of the home's feed is one component, not a set of page-local classes waiting in docs/DESIGN.md §5d. It moves to its own area file under docs/design/areas/, which scripts/design-lint.ts reads as vocabulary.

Done:

• [ ] A new docs/design/areas/feed.md names the component, what it is for, the function that draws it (src/web/studio/home.ts, styled in src/web/studio/feed_style.ts) and each class in a code span: .feed-head. Follow docs/design/areas/README.md.
• [ ] Each of those classes' own lines leaves §5d in docs/DESIGN.md. Only those lines.
• [ ] No markup and no stylesheet rule changes.
• [ ] bun scripts/design-lint.ts passes.

Files: docs/design/areas/feed.md (new), docs/DESIGN.md (deleting lines in §5d only). Risk: none; documentation only.

Planner addition: .feed (docs/DESIGN.md:581, beside .feed-head) belongs to the same component. Name it in docs/design/areas/feed.md too, and delete its §5d line.