Strip box-drawing (──) section dividers and ===/banner headers — visual
noise with no information. Where a divider label carried a non-obvious
why (VirtualList owns scrolling; mobile footer is md:hidden because header
stats take over) it is kept as a plain one-line comment; pure restatements
of the markup (Header bar, Red hover line, Bottom: fixed controls) are
dropped. Single comment style, no fluff.
Mock data lived in lib/ and was re-exported through the slice's
production index.ts, advertising fixtures as part of the public API.
Move it to a testing/ segment and drop it from index.ts; consumers now
import explicitly via the $entities/Font/testing subpath.
Repoints the four mock consumers (FontApplicator story, sizeResolver
and fontCatalogStore specs, comparisonStore test) to the new subpath.