feat(ui): the track list a phone can read

B2 phase 4, and the last of it. Measured on the device: at 424 CSS px
the four configured columns fit the row *exactly* -- `--grid-cols` came
out `24px 102px 101px 101px 80px` -- and not one of them fit its
content, with "Duration" too narrow for its own header. The columns were
never too wide; there were too many of them.

So a phone draws `titleArtist` (the title with the artist under it,
across the row's whole width) plus the duration, and drops the column
headers and the resize handles, which are a click-to-sort and a drag
with no touch equivalent. It is a **column set, not a second row
template**: the row, its delegated events, the selection semantics, the
playing marker and the virtualizer never learn anything changed, because
from their side only the number of columns did.

Three rules come with it. The row height is in two places
(`PHONE_ROW_HEIGHT` and the CSS rule) and must agree, since the
virtualizer positions rows from that number and a taller row overlaps
its neighbour. What is drawn and what can be sorted are different
questions, so the sort list is built from `configuredColumns` -- a phone
has no headers either, and building it from the drawn columns would
leave it able to sort by title and duration alone. And a phone's column
widths are neither loaded nor saved.

That third rule is the bug the device found with the arrangement already
passing five component tests and five e2e specs at the phone's own
viewport. `loadColumnWidths` is keyed by column *id* and fills a gap
with `MIN_COLUMN_WIDTH`, so the stacked column -- which nothing can ever
have saved a width for -- came out at 148px beside a duration column of
236. The mirror image was worse and unreachable from a phone at all:
saving would have written those widths back under the same ids,
replacing the width the user dragged on a desktop. The specs asserted
shape, and the fault depended on what `localStorage` held for a
different column set; the unit test now carries that map as a fixture.

Verified: 809 component tests, 112 e2e specs, and on the phone at
424x439 -- `24px 304px 80px`, 52px rows, no truncation, no overflow.
One full e2e run of three saw an unrelated autotag keypress spec flake
and pass on retry.

CLAUDE.md

@@ -1536,6 +1536,28 @@ by the three places that need them (the default widths, the
 normaliser, and the resize handles' positions), because they were
 written out separately and that is how they came to disagree.
 
+**A phone draws one column of two lines, and that is a column set
+rather than a second row template.** Measured on the device: at 424 px
+the four configured columns fit the row *exactly* (`--grid-cols` came
+out `24px 102px 101px 101px 80px`) and not one of them fit its content
+— "Duration" did not fit its own header. The columns were never too
+wide; there were too many of them. `PHONE_COLUMN_IDS` is `titleArtist`
+(title over artist, sharing the row's whole width) plus the duration, so
+the row, the delegated events, the selection semantics, the playing
+marker and the virtualizer are all untouched: from their side only the
+number of columns changed. Three rules come with it. **The row height
+lives in two places and they must agree** — `PHONE_ROW_HEIGHT` and the
+CSS rule — because the virtualizer positions rows from that number, so a
+taller row overlaps its neighbour. **What is drawn and what can be
+sorted are different questions**: the page header's sort list is built
+from `configuredColumns`, or a phone (which has no column headers
+either) could sort by nothing but title and duration. And **a phone's
+widths are neither loaded nor saved**: `loadColumnWidths` is keyed by
+column *id* and fills a gap with the minimum, so the stacked column —
+which nothing can ever have saved a width for — came out at 148 px
+beside a duration column of 236, and saving would have replaced the
+width the user dragged on a desktop for the same id.
+
 **The default columns are declared twice and must agree.**
 `tracklist.DefaultColumns` is what a fresh install persists;
 `DEFAULT_COLUMN_IDS` in `track-list/columns.ts` is what the list draws