chore(docs): copy vue flow files on dev build

docs/src/.vitepress/plugins/copy.ts

@@ -2,10 +2,7 @@ import { existsSync, readFileSync } from 'node:fs'
 import { resolve } from 'node:path'
 import type { Plugin } from 'vite'
 
-export function copyVueFlowPlugin(): Plugin {
-  return {
-    name: 'copy-vue-flow',
-    generateBundle() {
+function copyFiles(emit: any) {
   ;[
     { path: '../../../node_modules/@vue-flow/core/dist/', pkgName: 'vue-flow-core.mjs' },
     {
@@ -34,7 +31,7 @@ export function copyVueFlowPlugin(): Plugin {
       throw new Error(`${pkgName} not built. ` + `Run "pnpm -w build" first.`)
     }
 
-        ;(this as any).emitFile({
+    emit({
       type: 'asset',
       fileName: pkgName,
       source: readFileSync(filePath, 'utf-8'),
@@ -44,6 +41,18 @@ export function copyVueFlowPlugin(): Plugin {
   })
 
   console.log('Copied vue-flow files')
+}
+export function copyVueFlowPlugin(): Plugin {
+  return {
+    name: 'copy-vue-flow',
+    buildStart() {
+      copyFiles((file: any) => this.emitFile(file))
+    },
+    watchChange() {
+      copyFiles((file: any) => this.emitFile(file))
+    },
+    generateBundle() {
+      copyFiles((file: any) => this.emitFile(file))
     },
   }
 }