Browser fold arrows: each row is one widget with a stable id, and where the click lands decides what it does (fold arrow with padding, eye, radio, or the row), so an arrow click toggles without also selecting or picking the row or starting a drag; Collapse/Expand tips; ui.at {browser|chevron} and ui.browser for automation; scenario browser_chevrons clicks every folder's arrow (document settings, named views, origin, groups, sketches, construction, canvases, components, bodies, the design) and checks the children; the inch-width units test runs now that params reads unit-less lengths in design units

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL

crates/engine/src/cmd/browser.rs

@@ -442,7 +442,6 @@ mod tests {
     }
 
     #[test]
-    #[ignore = "waits for unit-less parameters used as lengths to read in the design's units (solvecraft-params)"]
     fn a_bare_width_keeps_its_inches_when_the_design_goes_metric() {
         let mut s = Session::default();
         run(&mut s, "document.units", json!({"units": "in"}));