feat(theme-studio): prev/next arrows to step the view dropdown

I added left and right arrow buttons flanking the view dropdown. They step the selection to the previous or next item and re-render the faces table and preview, so you can walk the list without reopening the dropdown. A pure stepViewIndex helper clamps the index to the option range, no wrap. stepView sets the selection and calls onViewChange.

1 files changed, 7 insertions, 0 deletions

diff --git a/scripts/theme-studio/app.js b/scripts/theme-studio/app.js
index 07ca06fe..f2c322aa 100644
--- a/scripts/theme-studio/app.js
+++ b/scripts/theme-studio/app.js
@@ -528,6 +528,13 @@ function buildViewSel(){const s=document.getElementById('viewsel');if(!s)return;
   const og=document.createElement('optgroup');og.label='package faces';
   for(const app of appViewKeysSorted(APPS))og.appendChild(mk(app,APPS[app].label));
   s.appendChild(og);}
+// The ‹ › buttons flanking the dropdown step the selection by DIR and re-render
+// the view (faces table + preview), so you can walk the list without reopening it.
+function stepView(dir){
+  const s=document.getElementById('viewsel');if(!s)return;
+  const i=stepViewIndex(s.selectedIndex,s.options.length,dir);
+  if(i!==s.selectedIndex){s.selectedIndex=i;onViewChange();}
+}
 function onViewChange(){const s=document.getElementById('viewsel');const v=(s&&s.value)||'@code';
   const show=(id,on)=>{const e=document.getElementById(id);if(e)e.style.display=on?'':'none';};
   show('view-code',v==='@code');show('view-ui',v==='@ui');show('view-pkg',v[0]!=='@');