Add n8n community node, /api/v1/render alias, and job webhooks for OSS automation.

Payment-free self-hosted builds keep full API access with optional webhookUrl callbacks and the published n8n-nodes-songs2vid package source under integrations/n8n.

lib/jobs/create-job.ts

@@ -292,11 +292,24 @@ export async function createVideoJob(
 
   await reserveQuota(user.id, items.length);
 
+  const webhookRaw = body.webhookUrl?.trim() || null;
+  if (webhookRaw) {
+    try {
+      const u = new URL(webhookRaw);
+      if (u.protocol !== "https:" && u.protocol !== "http:") {
+        throw new Error("webhookUrl must be http(s)");
+      }
+    } catch {
+      throw new Error("Invalid webhookUrl. Provide an absolute http(s) URL for n8n callbacks.");
+    }
+  }
+
   try {
     const job = await prisma.job.create({
       data: {
         userId: user.id,
         imagePath,
+        webhookUrl: webhookRaw,
         items: {
           create: items.map((item, index) => {
             const wm = applyBrandWatermarkPolicy(