perf(electrobun): fix CEF high CPU — disable GPU flags + remove CSS animations

- electrobun.config.ts: add --disable-gpu --disable-gpu-compositing to CEF
  flags (GLXBadWindow X11 errors cause continuous recovery loop)
- StatusBar.svelte: replace @keyframes pulse with CSS transition + JS toggle
- app.css: remove @keyframes pulse-dot (continuous compositor repaint)

CSS animations on small elements cause 10-30% CPU in both CEF and WebKitGTK.
JS class toggle with transition: opacity 0.3s uses near-zero CPU.

ui-electrobun/src/mainview/app.css

@@ -219,10 +219,8 @@ html, body {
   --dot-color: var(--ctp-peach);
 }
 
-@keyframes pulse-dot {
-  0%, 100% { opacity: 1; transform: scale(1); }
-  50%       { opacity: 0.55; transform: scale(0.85); }
-}
+/* @keyframes pulse-dot removed — CSS animations cause continuous repaint
+   in CEF + WebKitGTK. Use JS class toggle instead. */
 
 .project-name {
   font-weight: 600;