feat(ui): refresh layout, help assets, and panel styling

Update the main template and client scripts for the revised navigation
and zone/device panels, and add bundled help SVG assets under static.

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/images/help/header-toolbar.svg

@@ -2,7 +2,7 @@
   <title>Header: tab buttons and action bar</title>
   <rect width="820" height="108" fill="#1a1a1a"/>
   <rect x="0" y="106" width="820" height="2" fill="#4a4a4a"/>
-  <text x="16" y="28" fill="#888" font-family="sans-serif" font-size="11">Tabs</text>
+  <text x="16" y="28" fill="#888" font-family="sans-serif" font-size="11">Zones</text>
   <rect x="16" y="40" width="72" height="36" rx="4" fill="#333" stroke="#666" stroke-width="1"/>
   <text x="34" y="63" fill="#ccc" font-family="sans-serif" font-size="13">default</text>
   <rect x="96" y="40" width="88" height="36" rx="4" fill="#2a4a7a" stroke="#5a8fd4" stroke-width="2"/>
@@ -13,7 +13,7 @@
   <rect x="380" y="40" width="72" height="30" rx="3" fill="#3d3d3d" stroke="#555" stroke-width="1"/>
   <text x="396" y="59" fill="#e0e0e0" font-family="sans-serif" font-size="11">Profiles</text>
   <rect x="458" y="40" width="52" height="30" rx="3" fill="#3d3d3d" stroke="#555" stroke-width="1"/>
-  <text x="470" y="59" fill="#e0e0e0" font-family="sans-serif" font-size="11">Tabs</text>
+  <text x="470" y="59" fill="#e0e0e0" font-family="sans-serif" font-size="11">Zones</text>
   <rect x="516" y="40" width="64" height="30" rx="3" fill="#3d3d3d" stroke="#555" stroke-width="1"/>
   <text x="524" y="59" fill="#e0e0e0" font-family="sans-serif" font-size="11">Presets</text>
   <rect x="586" y="40" width="78" height="30" rx="3" fill="#3d3d3d" stroke="#555" stroke-width="1"/>