Each rendered comment gets a "Reply" action (shown whenever the
viewer has write access, regardless of authorship). Clicking it
prefills the comment editor with a <blockquote data-comment-id="X">
wrapping the parent body so the canonical reply marker is the
blockquote itself.
A Vue NodeView on the blockquote extension renders an author
header + chevron when an injected commentReplyContext can resolve
the parent. The chevron scrolls to and briefly highlights the
original. Quotes whose parent isn't in the in-memory list (deleted,
on another page) render a degraded header with the chevron hidden.
kolaente