When users switch between the Layers and Assets sidebar tabs, the
`assets-toolbox*` component unmounts and its local `use-state` is
discarded, so the search query and section filter are lost.
Lift the search term and section filter into a per-file, in-memory
session atom that survives tab switches but doesn't leak across files
or persist across reloads. Ordering and list-style continue to use
localStorage as before.
Closes#2913
Signed-off-by: eureka0928 <meobius123@gmail.com>
Co-authored-by: Andrey Antukh <niwi@niwi.nz>
68595e90eb