Fix connection edge incorrect position

Author: j-sanaa

packages/agentflow/src/features/canvas/components/NodeInputHandle.tsx

@@ -25,7 +25,9 @@ function NodeInputHandleComponent({ nodeId, nodeColor, hidden }: NodeInputHandle
             backgroundColor: 'transparent',
             border: 'none',
             position: 'absolute' as const,
-            left: HANDLE_OFFSET
+            left: HANDLE_OFFSET,
+            top: '50%',
+            transform: 'translateY(-50%)'
         }),
         []
     )