ui: enlarge the header sim/nosim icon to 30px

- the SVG artwork occupies only ~46% x 63% of its 183x183 canvas, so
  the 18px render showed ~8x11px of ink; 30px roughly doubles the
  visible glyph while staying under the 32px h1 line-height, so the
  header row height is unchanged
- guard test asserts the inline size stays within the 24-32px budget;
  SW cache v112 -> v113.

frontend/index.html

@@ -22,7 +22,7 @@
 		<div class="flex items-center gap-4">
 			<span id="state-indicator" class="flex items-center select-none" style="cursor:default" title="Connecting...">
 				<span id="state-indicator-dot" class="text-xs text-gray-400" title="Connecting...">●</span>
-				<img id="state-indicator-img" class="hidden dark:invert" style="width:18px;height:18px" alt="" src="nosim.svg">
+				<img id="state-indicator-img" class="hidden dark:invert" style="width:30px;height:30px" alt="" src="nosim.svg">
 			</span>
 			<button id="install-btn" class="px-2 py-1 text-xs rounded border border-gray-300 dark:border-slate-600 hover:bg-gray-200 dark:hover:bg-slate-700" style="display:none">INSTALL PWA [for offline use]</button>
 			<a href="https://github.com/anttro/otaman" target="_blank" class="text-xs text-gray-400 hover:text-gray-600 dark:text-slate-500 dark:hover:text-slate-300">github</a>