⚡ Bolt: Execute independent network requests concurrently to reduce latency

[Snigdh41]

💡 What:
Batched the two Resend email API calls (buildNotificationEmail and buildAutoReplyEmail) in workers/contact-api/src/index.js using Promise.all() to allow them to execute concurrently.

🎯 Why:
The Cloudflare worker was previously awaiting each external network request sequentially. Since sending the notification email and the auto-reply email do not depend on each other, executing them in parallel eliminates the accumulated latency of sequential requests.

📊 Impact:
Reduces the external network delay portion of the worker's execution time by approximately half (from T_send1 + T_send2 to max(T_send1, T_send2)), resulting in faster overall response times for the contact API.

🔬 Measurement:
Observe the execution time of the /contact API endpoint before and after the change; the time spent on sending emails will be reduced, which can be verified in network tab timings or Cloudflare Worker metrics.

---

PR created automatically by Jules for task 7767395905046583021 started by @Snigdh41

[google-labs-jules]

👋 Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

New to Jules? Learn more at jules.google/docs.

---

For security, I will only act on instructions from the user who triggered this task.