Polish Bento scrolling and controls with full screen coverage

frontend/glass-controls.test.js

@@ -13,3 +13,10 @@ test('playlist trash, menu and music glyphs use drawn glass icons',()=>{
  assert.equal(leadingGlyph('⋮').kind,'more');
  assert.equal(leadingGlyph('🎵').kind,'music');
 });
+
+test('Bento-only legacy icons leave the Glass glyph set unchanged',()=>{
+ assert.equal(leadingGlyph('📺 Show video'),null);
+ assert.deepEqual(leadingGlyph('📺 Show video',true),{kind:'television',original:'📺',rest:' Show video'});
+ assert.equal(leadingGlyph('⏱ Tap-sync',true).kind,'clock');
+ assert.equal(leadingGlyph('📌 Bookmark',true).kind,'pin');
+});