refactor(canvas): remove unused animation and optimize edge insertion timing

- Removed the unused CSS animation for edge insertion to streamline the codebase.
- Updated the edge insertion reflow duration from 1297ms to 997ms for improved performance.
- Refactored transition timing function for edge insertion to enhance animation smoothness.
- Cleaned up related test cases to reflect the changes in edge insertion logic.

app/globals.css

@@ -145,17 +145,6 @@
   }
 }
 
-@keyframes ls-edge-insert-enter {
-  0% {
-    opacity: 0;
-    scale: 0.82;
-  }
-  100% {
-    opacity: 1;
-    scale: 1;
-  }
-}
-
 .ls-connection-line-marching {
   animation: ls-connection-dash-offset 0.4s linear infinite;
 }
@@ -262,17 +251,52 @@
   .react-flow.canvas-edge-insert-reflowing .react-flow__node {
     transition-property: transform;
     transition-duration: var(--ls-edge-insert-reflow-duration, 1297ms);
-    transition-timing-function: cubic-bezier(0.68, -0.6, 0.32, 1.6);
+    transition-timing-function: linear(
+      0 0%,
+      0.2718 2.5%,
+      0.6464 5%,
+      1 7.5%,
+      1.25 10%,
+      1.3641 12.5%,
+      1.3536 15%,
+      1.2575 17.5%,
+      1.125 20%,
+      1 22.5%,
+      0.9116 25%,
+      0.8713 27.5%,
+      0.875 30%,
+      0.909 32.5%,
+      0.9558 35%,
+      1 37.5%,
+      1.0313 40%,
+      1.0455 42.5%,
+      1.0442 45%,
+      1.0322 47.5%,
+      1.0156 50%,
+      1 52.5%,
+      0.989 55%,
+      0.9839 57.5%,
+      0.9844 60%,
+      0.9886 62.5%,
+      0.9945 65%,
+      1 67.5%,
+      1.0039 70%,
+      1.0057 72.5%,
+      1.0055 75%,
+      1.004 77.5%,
+      1.002 80%,
+      1 82.5%,
+      0.9986 85%,
+      0.998 87.5%,
+      0.998 90%,
+      0.9986 92.5%,
+      0.9993 95%,
+      1 97.5%,
+      1 100%
+    );
     will-change: transform;
   }
 
-  .react-flow__node.canvas-edge-insert-enter,
-  .react-flow__node .canvas-edge-insert-enter {
-    animation: ls-edge-insert-enter 300ms cubic-bezier(0.68, -0.6, 0.32, 1.6) both;
-    transform-origin: center center;
-    will-change: scale, opacity;
-  }
-
   @media (prefers-reduced-motion: reduce) {
     .react-flow.canvas-scissors-mode .react-flow__edge:not(.temp) .react-flow__edge-path {
       transition: none;
@@ -281,13 +305,5 @@
     .react-flow.canvas-edge-insert-reflowing .react-flow__node {
       transition: none;
     }
-
-    .react-flow__node.canvas-edge-insert-enter,
-    .react-flow__node .canvas-edge-insert-enter {
-      animation: none;
-      opacity: 1;
-      scale: 1;
-      will-change: auto;
-    }
   }
 }