fix(workspace): move lane list to a vertical column beside detail panel

The detail panel (LaneCard/PipelineMap/proof gallery/console) could
grow tall enough to visually crowd out the lane-strip carousel above
it once a run was attached in split view. Move the lane list into its
own scrolling vertical column beside the detail panel instead of
stacking it above, so neither can cover the other; also collapse the
info block by default in 2/4-pane split view (toggle to expand) and
move the pane-count control into the detail header.

client/src/i18n/locales/en/lanes.json

@@ -90,6 +90,8 @@
   "git.uncommitted": "{{dirty}} modified · {{untracked}} untracked",
   "kind.adopted": "adopted",
   "kind.managed": "managed",
+  "laneDetail.hide": "Hide details",
+  "laneDetail.show": "Lane details",
   "laneHeader": "Lane {{id}} · {{title}} · {{pipeline}}",
   "locks.held_one": "{{count}} lock held",
   "locks.held_other": "{{count}} locks held",