✨ Implement newsletter subscription form using API

Switch from SendInBlue to EmailOctopus for newsletter. Now uses their API through the form to handle subscription.

src/routes/api/newsletter.ts

@@ -0,0 +1,44 @@
+import type { RequestEvent, RequestHandlerOutput } from '@sveltejs/kit'
+
+
+// Block GET requests
+export async function get({}: RequestEvent): Promise<RequestHandlerOutput> {
+    return {
+        status: 403,
+        body: 'nope!'
+    }
+}
+
+
+/**
+ * POST request
+ */
+export async function post ({ request }: RequestEvent): Promise<RequestHandlerOutput> {
+    const body = await request.text()
+
+    if (body) {
+        const req = await fetch(`https://emailoctopus.com/api/1.6/lists/${import.meta.env.VITE_NEWSLETTER_LIST_ID}/contacts`, {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify({
+                api_key: import.meta.env.VITE_NEWSLETTER_API_TOKEN,
+                email_address: body,
+            })
+        })
+        const res = await req.json()
+
+        if (res && res.email_address && res.status === 'PENDING') {
+            return {
+                status: 200,
+                body: {
+                    code: 'PENDING'
+                },
+            }
+        }
+
+        return {
+            status: 403,
+            body: res.error,
+        }
+    }
+}