feat: add post-build-script to gradually migrate

packages/file-graph/post-build-script.js

@@ -0,0 +1,20 @@
+import fs from 'fs'
+import path from 'path'
+
+function addJsExtension(filePath) {
+  if (fs.statSync(filePath).isDirectory()) {
+    for (const child of fs.readdirSync(filePath)) {
+      addJsExtension(path.join(filePath, child))
+    }
+  } else if (filePath.endsWith('.js')) {
+    let content = fs.readFileSync(filePath, 'utf8')
+    content = content.replace(/from\s+["']([^"']+)["']/g, (match, group1) => {
+      if (!group1.match(/^[./]|http|https/)) return match // Skip node_modules
+      if (!group1.endsWith('.js')) return `from "${group1}.js"`
+      return match
+    })
+    fs.writeFileSync(filePath, content, 'utf8')
+  }
+}
+
+addJsExtension('./dist')