fix: lazy-resolve useRuntimeConfig in withSigning

Avoids pulling nitro virtual modules (#imports) into unit tests that
import handler files for their exported utilities (e.g. instagram-embed
exports rewriteUrl/scopeCss alongside its default handler). The dynamic
import only runs at request time inside the nitro runtime where #imports
is available.

Author: harlan-zw

packages/script/src/runtime/server/utils/withSigning.ts

@@ -21,14 +21,17 @@
  */
 
 import type { EventHandler, EventHandlerRequest, EventHandlerResponse } from 'h3'
-import { useRuntimeConfig } from '#imports'
 import { createError, defineEventHandler } from 'h3'
 import { verifyProxyRequest } from './sign'
 
 export function withSigning<Req extends EventHandlerRequest = EventHandlerRequest, Res extends EventHandlerResponse = EventHandlerResponse>(
   handler: EventHandler<Req, Res>,
 ): EventHandler<Req, Res> {
   return defineEventHandler<Req>(async (event) => {
+    // Lazy-resolve useRuntimeConfig to avoid pulling nitro's virtual modules
+    // into unit tests that import handler files for their exported utilities
+    // (e.g. instagram-embed.ts exports rewriteUrl / scopeCss alongside the handler).
+    const { useRuntimeConfig } = await import('#imports')
     const runtimeConfig = useRuntimeConfig(event)
     const secret = (runtimeConfig['nuxt-scripts'] as { proxySecret?: string } | undefined)?.proxySecret