The button floats over the bottom-right corner, and at the end of a long table it covered the closing
pager's '100' and 'All'. While it is up, PageScroller ends the page a button's height later (only
then, so a full-height layout gets no scrollbar). Its shown state is a shared store read through a
use… wrapper: a store's .use() called straight from a component is memoized by the React Compiler
and never re-renders (contract: store.contract.test.ts).
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.