The install registry picker used MenuSurface and overrode the theme-owned
menu material tokens, which the shared-menu-material gate rejects. Return
the picker to a fieldset (its native group role) and paint an opaque
bg-layer-2 surface so the form controls stay readable without touching
menu tokens. This also restores the group's radios to the accessible tree.
Align plugin-install-registry.e2e and its snapshots with the PR's visible
text: registry option names drop the parentheses around the host, the
custom address field is no longer disabled, and the custom hint spells out
http(s) and ~/.npmrc.
Hold the manual-refresh spinner to a 400ms minimum so a fast read does not
flash it, clearing to idle (or the failure toast) only after the minimum,
and dropping a refresh that settles after disposal.
Prune the retired no-unknown-casts baseline entry for browser-plugin.client.spec.