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/StatusBar.svelte

@@ -178,13 +178,11 @@
   .dot.orange { background: var(--ctp-peach); }
 
   .pulse-dot {
-    animation: pulse 1.5s ease-in-out infinite;
-  }
-
-  @keyframes pulse {
-    0%, 100% { opacity: 1; }
-    50% { opacity: 0.3; }
+    /* No CSS animation — use JS class toggle to avoid continuous repaint.
+       CEF + WebKitGTK both suffer from high CPU with @keyframes on small elements. */
+    transition: opacity 0.3s ease;
   }
+  .pulse-dot.dim { opacity: 0.4; }
 
   .val { color: var(--ctp-text); font-weight: 500; }
   .cost { color: var(--ctp-yellow); }