fix(electrobun): restore CSS animations for WebKitGTK user mode

CSS pulse animations restored — they run at ~0% CPU on WebKitGTK's
native compositor. The --disable-gpu flags in electrobun.config.ts
only apply in CEF mode (AGOR_CEF=1) for E2E testing.

User mode (WebKitGTK): full GPU, full animations, full transitions
Test mode (CEF): GPU disabled, animations still CSS but no human watching

ui-electrobun/src/mainview/app.css

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