feat(web): light the open toggles and halve the key dock

Search, History, the keys dock and the quick dock rendered pixel identical
open or closed, so the only clue a panel was up was the panel itself. Every
toggle in the session view now carries `aria-pressed`, written only by
`setPressed`, and the CSS fills the chip off that attribute -- so the pixels
and the screen reader cannot drift apart. The fill is the inverted neutral
(`--text` on `--bg`): unmistakably lit, no semantics of its own to clash with
the orange/red keys, and the one pair of colours that contrasts in all eleven
themes. A blue fill was tried first and read as a second Send button beside
the real one, so blue now means selection only (the Keys/123 switch, the Tools
filter). `refresh` keeps no pressed state at all -- it fires and returns, and
that contrast is what marks the two chips beside it as toggles.

Mutually exclusive pairs are restated together instead of one at a time, which
is where the old code lost track: `showDock` sets both dock buttons, and
`toggleSearch` closes history through `navClose` rather than hiding the
element and orphaning its history entry.

Measured at 390x844, with presets closed / open: the keys pad went 205 -> 121
and 301 -> 201 by folding the pad switch and the presets disclosure onto one
line and going seven columns wide by two rows. Twelve keys need thirteen cells
because of the arrows' empty corner, so seven is the narrowest grid that fits
two rows; Enter spans both. The same pass found the digit pad had become the
tallest dock at 223px -- 3x3 of 52px keys for nine single characters -- and put
it in one row of nine (85px), and cut the quick dock's two labelled sections to
a 3x2 grid (219 -> 121), since colour already said which two were the confirm
pair. Nothing clips down to a 320px viewport, at 40px a cell.

The history panel now asks for tool turns by default. A tool call is most of
what an agent's turn consists of -- 674 of 794 on the largest session here --
so hiding them rendered a conversation with holes in it. It costs reach, since
tool turns spend page slots and characters from the same budget as the prose;
the Tools chip is the way back to prose-only. The relay's own default is
unchanged.