Second slice of the E11 keyboard layer (S4b). S4a gave the feed, the library and the channel page
`j`/`k`, the arrows and Enter; Home's shelves and the whole Plex module were still Tab-stop country —
a Plex poster is its own Tab stop, and a rail's cards sat behind every control of the cards before.
- `lib/listNav`: a list that mounts every item no longer declares a count or columns — both are
measured off the DOM when a key is pressed, so an auto-fill grid's columns follow its width and a
rail is one row. ↑ on a list's top row and ↓ on its bottom row go on to the neighbouring list, onto
the item horizontally nearest the one left (owner decision D4: ←→ within a rail, ↑↓ to the rail
above or below). The first `j` skips cards a rail has scrolled out to the left.
- `Carousel keyboardNav` registers the scroller; the scroller gets a 4px inset (against a -4px margin,
layout unchanged) so the focus ring is not clipped, and `[data-nav-index]` a 2.5rem inline scroll
margin so a card stepped into view clears the rail's edge fade and paging arrow.
- `ui/NavGrid`: the plain, fully mounted grid that registers itself.
- `navIndex` on PlexPosterCard / SeasonCard / EpisodeCard (the card root is the item, the poster the
open element — the ring goes round poster and title, D2), PosterTile and Home's ShelfTile (the button
is the item); cast, related and collection-strip buttons carry the attrs directly.
- Wired: Home's comfort and resume rails; Plex Browse titles + episodes, Discover rails + genres,
collection view, playlists/collections browse, person known-for + filmography, show seasons, season
episodes, cast/related strips, info-page cast + collection strips.
- `listNav.wiring.contract.test`: every `Carousel` says `keyboardNav`, every card says `navIndex`, and a
card with `navIndex` sits inside a NavGrid / Carousel / VirtualGrid — both halves are opt-in, and
either one missing leaves a list the keyboard silently skips.
The app HAS a platform layer -- AnchoredPopover (22 importers, with
arrows/typeahead/Escape/anchor-flip), QueryState (21), Modal (17),
PageShell, DataTable, Tabs, Tooltip and ~26 more -- but it sat flat among
~160 feature components with nothing marking it as one. Several of those
files describe themselves as 'the one place' or 'canonical' and were
still bypassed by hand-rolled markup, because a layer nobody can see is a
layer nobody uses; three separate inventory passes of this codebase
misread it the same way.
Moves the 33 domain-free modules into components/ui/, rewrites the
imports in 89 files, and makes the boundary a lint rule rather than a
convention: inside ui/ a one-level-up import (a feature component) and
any lib/api slice are errors. The rule was verified to fire on both and
to leave generic lib/ helpers alone. README.md states which side of the
line a component belongs on and why.
No behaviour change: 3x tsc, eslint, knip, prettier and 687 vitest tests
all green; no backend file touched.
peter