Comment cleanup: UI primitives (63/84)

[ianu82]

Condense redundant comments in UI primitives so maintainers can find the constraints without reading repeated walkthroughs and implementation history. Useful contracts, compatibility notes and tool directives are preserved.

This is part 63 of the full Cowork comment cleanup. It contains 1 files, +0/−4 lines (4 net lines removed), capped at 600 added/deleted lines for review.

Targets staging independently. This patch has no dependency on the other cleanup PRs.

Scope

• src/renderer/cowork/components/ui/index.js

Validation

• This branch's file contents and diff match the reviewed local patch, with an unchanged staging baseline (ffad088).
• The complete cleanup passed 335 suites: 3,861 tests passed and one skipped, with coverage floors satisfied. Type checking, the Cowork purity check and the renderer production build passed.
• Structural checks confirmed equivalent JS/TS source or emitted ASTs, unchanged typed JSDoc and functional directives, equivalent CSS/YAML/HTML where applicable, and unchanged executable script content.
• Individual PRs have not each rerun the whole suite locally; GitHub checks report branch-specific results. No test assertions or executable logic are edited by this patch.

The full set removes 17,018 lines (9.9% of the reviewed source/build tree), including a 55.1% reduction in JS/TS comment-bearing lines.

[github-actions]

No PR environment for this pull request

Add the deploy label and push to create one. It is torn down when the label is removed or the PR closes, so any URL you saw here earlier is gone.

_{Updated on every push to this PR.}