fix: replace SVG animate with CSS animation for basic edge to prevent bounce

SVG <animate> restarts on every React re-render (especially visible under
StrictMode double-invoke in dev), causing a visible bounce. CSS animation
runs on the compositor thread independently of React renders.

frontend/src/index.css

@@ -6,6 +6,11 @@
 
 @custom-variant dark (&:is(.dark *));
 
+@keyframes homelable-basic-dash {
+  from { stroke-dashoffset: 10; }
+  to   { stroke-dashoffset: 0; }
+}
+
 /* Homelable dark theme — always dark */
 :root {
     --background: #0d1117;