feat: the frontend part of mcp (#22131)

Co-authored-by: jZonG <jzongcode@gmail.com>
Co-authored-by: Novice <novice12185727@gmail.com>
Co-authored-by: nite-knite <nkCoding@gmail.com>
Co-authored-by: Hanqing Zhao <sherry9277@gmail.com>

web/app/components/workflow/block-selector/use-check-vertical-scrollbar.ts

@@ -0,0 +1,31 @@
+import { useEffect, useState } from 'react'
+
+const useCheckVerticalScrollbar = (ref: React.RefObject<HTMLElement>) => {
+  const [hasVerticalScrollbar, setHasVerticalScrollbar] = useState(false)
+
+  useEffect(() => {
+    const elem = ref.current
+    if (!elem) return
+
+    const checkScrollbar = () => {
+      setHasVerticalScrollbar(elem.scrollHeight > elem.clientHeight)
+    }
+
+    checkScrollbar()
+
+    const resizeObserver = new ResizeObserver(checkScrollbar)
+    resizeObserver.observe(elem)
+
+    const mutationObserver = new MutationObserver(checkScrollbar)
+    mutationObserver.observe(elem, { childList: true, subtree: true, characterData: true })
+
+    return () => {
+      resizeObserver.disconnect()
+      mutationObserver.disconnect()
+    }
+  }, [ref])
+
+  return hasVerticalScrollbar
+}
+
+export default useCheckVerticalScrollbar