Storage and Timeline take the arrow keys but not the wheel

[bmethod]

Source: noted while building the wheel handling in phase 3 of #24, 2026-09-09.
Re-audited 2026-09-10 against origin/issue-24-design at 685e3e8, where the
Timeline half turns out to be one prop rather than a new handler.

Reached by: open Storage or Timeline and turn the mouse wheel over the list.
Nothing moves. The same wheel moves the selection on Agents, the Agents table,
Resources and Builds.

Timeline: the shared list is already there, without its wheel

src/ui/timeline-screen.tsx:392-421 renders the change list through the shared
List, and passes items, selected, height, empty and render — but not
onSelect. src/ui/widgets.tsx:486 gates the wheel on exactly that prop:
onMouseScroll={onSelect && …}. The two screens that respond to the wheel pass
it (src/ui/agents.tsx:750, :787).

So Timeline needs a selection setter passed down, not a wheel handler of its own.

Storage: a scroll container, not a windowed list

src/ui/storage-screen.tsx:304 opens a <scrollbox> and :138 keeps the
selection visible with scroller.current?.scrollChildIntoView. This one is a real
choice: either move it onto the shared List, or give the container a wheel
handler that moves the selection rather than the scroll offset.

A reader who has learned the wheel on four screens will try it on the other two.

Done when

• The wheel moves the selection on the Storage list and on the Timeline change
  list, one row per notch, the same as elsewhere.
• A test drives each by wheel and asserts the selection moved by one.

Context

• Location: src/ui/timeline-screen.tsx (pass onSelect),
  src/ui/storage-screen.tsx, and the wheel handling in src/ui/widgets.tsx.
• Related: A fast wheel advances the selection by one row, not by several #46, the same handler at src/ui/widgets.tsx:486-495, where a fast
  flick advances one row instead of several. Worth doing in the same change.
• Storage is the only screen left with a second scrolling implementation. A second
  implementation of the same behaviour is how the two drift apart.

[linear-code]

VSY-20