Use newsletter-api for immediate welcome emails

Switches from direct Listmonk API to newsletter-api endpoint
which handles subscription + sends welcome email immediately.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

components/newsletter-signup.tsx

@@ -2,7 +2,7 @@
 
 import { useState } from "react"
 
-const LISTMONK_URL = "https://newsletter.jeffemmett.com"
+const NEWSLETTER_API = "https://newsletter.jeffemmett.com/api/subscribe"
 const LIST_UUID = "df598d1a-4bed-4a8b-8c36-a5a6346febf0" // Trippin list
 
 export function NewsletterSignup() {
@@ -18,21 +18,20 @@ export function NewsletterSignup() {
     setStatus("loading")
 
     try {
-      const response = await fetch(`${LISTMONK_URL}/subscription/form`, {
+      const response = await fetch(`${NEWSLETTER_API}/subscribe`, {
         method: "POST",
         headers: {
-          "Content-Type": "application/x-www-form-urlencoded",
+          "Content-Type": "application/json",
         },
-        body: new URLSearchParams({
+        body: JSON.stringify({
           email: email,
-          list: LIST_UUID,
-          name: "",
+          list_uuid: LIST_UUID,
         }),
       })
 
       if (response.ok) {
         setStatus("success")
-        setMessage("Check your email to confirm your subscription!")
+        setMessage("The doors are open. Keep trippin'.")
         setEmail("")
       } else {
         throw new Error("Subscription failed")