Both views are toggled from the header and read from the same ladder: one
segment per volume the series should have, coloured read, reading, in library
or missing. Gaps were previously only on the series detail page, so the list
could never say a volume was absent; a Gaps filter now decides that in SQL,
mirroring the existing gap finder branch for branch so the two surfaces can
never disagree.
The card's fanned covers are laid out from cached percentages against an
aspect-ratio box, so nothing is measured at runtime and hover spreads the fan
through one custom property instead of per-cover reactive state.
See docs/COMMIT_GUIDELINES.md for the API additions to SeriesSummary.
neon