feat(ui): upright icon tabs on the right rail, never shrunk or clipped

The rail tabs show one Material Symbols glyph each (Display tune, CCTV
videocam, Street Level streetview, Context travel_explore, Weather cloud,
Recent Imagery satellite_alt) in a fixed 34px square, the size of the Radio
launcher under them. The panel's translated title is the tab's aria-label and
tooltip. The sideways labels, the equal share of a short strip, the end fade
and the column's lane cap are gone: every tab stays whole, and on the shortest
windows the strip runs past the lane instead of clipping. The glyphs join the
icon font subset, with a test that keeps them there. The screenshot is
refreshed.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

index.html

@@ -26,7 +26,7 @@
        with the sources: src/materialSymbolsSubset.test.mjs fails when a source
        names a glyph this list is missing, because a missing glyph does not draw
        a box — the ligature never forms and the element renders the literal word. -->
-  <link href="https://fonts.googleapis.com/css2?family=Material+Symbols+Outlined:opsz,wght,FILL,GRAD@20,400,0,0&icon_names=adjust,arrow_drop_down,arrow_forward,arrow_left,arrow_right,bolt,chevron_left,chevron_right,close,close_fullscreen,dark_mode,draw,east,flare,flight,layers,layers_clear,light_mode,local_fire_department,more_horiz,my_location,navigation,normal,on,open_in_full,public,radar,radio,right_panel_close,right_panel_open,rocket_launch,search,settings,skip_next,skip_previous,upload_file,videocam,view_in_ar,visibility,visibility_off" rel="stylesheet" />
+  <link href="https://fonts.googleapis.com/css2?family=Material+Symbols+Outlined:opsz,wght,FILL,GRAD@20,400,0,0&icon_names=adjust,arrow_drop_down,arrow_forward,arrow_left,arrow_right,bolt,chevron_left,chevron_right,close,close_fullscreen,cloud,dark_mode,draw,east,flare,flight,layers,layers_clear,light_mode,local_fire_department,more_horiz,my_location,navigation,normal,on,open_in_full,public,radar,radio,right_panel_close,right_panel_open,rocket_launch,satellite_alt,search,settings,skip_next,skip_previous,streetview,travel_explore,tune,upload_file,videocam,view_in_ar,visibility,visibility_off" rel="stylesheet" />
 </head>
 <body>
   <!-- gev:template scene-chrome -->