fix: defer Resend initialization to request time

Instantiating Resend at module load crashes the dev server when
RESEND_API_KEY is not set. Move initialization inside the handler
and add a missing-key guard.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Arckie Jadulco

server/api/contact.post.ts

@@ -1,7 +1,5 @@
 import { Resend } from 'resend'
 
-const resend = new Resend(process.env.RESEND_API_KEY)
-
 export default defineEventHandler(async (event) => {
   const { name, email, message } = await readBody(event)
 
@@ -12,7 +10,13 @@ export default defineEventHandler(async (event) => {
     throw createError({ statusCode: 400, statusMessage: 'Invalid email address' })
   }
 
+  const apiKey = process.env.RESEND_API_KEY
+  if (!apiKey) {
+    throw createError({ statusCode: 500, statusMessage: 'Email service not configured' })
+  }
+
   try {
+    const resend = new Resend(apiKey)
     await resend.emails.send({
       from: 'Portfolio Contact <noreply@arckiejadulco.dev>',
       to: 'arckie.jadulco@gmail.com',