fix(webhooks): Use SONARR_INSTANCES/RADARR_INSTANCES config for notification routes

The notification routes were using process.env.SONARR_URL directly,
which is undefined when using the newer SONARR_INSTANCES JSON format.

Changes:
- Added getFirstSonarrInstance() and getFirstRadarrInstance() helpers
- Updated /notifications, /notifications/test, and /notifications/sofarr-webhook
  routes to use instance config from getSonarrInstances()/getRadarrInstances()
- Returns 503 error if no instances are configured

Fixes: 'Invalid URL' errors when calling Sonarr/Radarr notification APIs

server/routes/radarr.js

@@ -4,7 +4,16 @@ const axios = require('axios');
 const router = express.Router();
 const requireAuth = require('../middleware/requireAuth');
 const sanitizeError = require('../utils/sanitizeError');
-const { getWebhookSecret, getSofarrBaseUrl } = require('../utils/config');
+const { getWebhookSecret, getSofarrBaseUrl, getRadarrInstances } = require('../utils/config');
+
+// Helper to get first Radarr instance (for notification proxy routes)
+function getFirstRadarrInstance() {
+  const instances = getRadarrInstances();
+  if (!instances || instances.length === 0) {
+    return null;
+  }
+  return instances[0];
+}
 
 router.use(requireAuth);
 
@@ -60,9 +69,13 @@ router.get('/movies', async (req, res) => {
 // Notification proxy routes (Phase 3)
 // GET /api/radarr/notifications - list all notifications
 router.get('/notifications', async (req, res) => {
+  const instance = getFirstRadarrInstance();
+  if (!instance) {
+    return res.status(503).json({ error: 'Radarr not configured' });
+  }
   try {
-    const response = await axios.get(`${process.env.RADARR_URL}/api/v3/notification`, {
-      headers: { 'X-Api-Key': process.env.RADARR_API_KEY }
+    const response = await axios.get(`${instance.url}/api/v3/notification`, {
+      headers: { 'X-Api-Key': instance.apiKey }
     });
     res.json(response.data);
   } catch (error) {
@@ -121,9 +134,13 @@ router.delete('/notifications/:id', async (req, res) => {
 
 // POST /api/radarr/notifications/test - test notification
 router.post('/notifications/test', async (req, res) => {
+  const instance = getFirstRadarrInstance();
+  if (!instance) {
+    return res.status(503).json({ error: 'Radarr not configured' });
+  }
   try {
-    const response = await axios.post(`${process.env.RADARR_URL}/api/v3/notification/test`, req.body, {
-      headers: { 'X-Api-Key': process.env.RADARR_API_KEY }
+    const response = await axios.post(`${instance.url}/api/v3/notification/test`, req.body, {
+      headers: { 'X-Api-Key': instance.apiKey }
     });
     res.json(response.data);
   } catch (error) {
@@ -150,6 +167,10 @@ router.get('/notifications/schema', async (req, res) => {
 
 // POST /api/radarr/notifications/sofarr-webhook - one-click Sofarr webhook setup
 router.post('/notifications/sofarr-webhook', async (req, res) => {
+  const instance = getFirstRadarrInstance();
+  if (!instance) {
+    return res.status(503).json({ error: 'Radarr not configured' });
+  }
   try {
     const sofarrBaseUrl = getSofarrBaseUrl();
     const webhookSecret = getWebhookSecret();
@@ -164,8 +185,8 @@ router.post('/notifications/sofarr-webhook', async (req, res) => {
     const webhookUrl = `${sofarrBaseUrl}/api/webhook/radarr`;
 
     // Check if Sofarr webhook already exists
-    const listResponse = await axios.get(`${process.env.RADARR_URL}/api/v3/notification`, {
-      headers: { 'X-Api-Key': process.env.RADARR_API_KEY }
+    const listResponse = await axios.get(`${instance.url}/api/v3/notification`, {
+      headers: { 'X-Api-Key': instance.apiKey }
     });
     const existingNotification = listResponse.data.find(n => n.name === 'Sofarr');
 
@@ -190,17 +211,17 @@ router.post('/notifications/sofarr-webhook', async (req, res) => {
     if (existingNotification) {
       // Update existing notification
       const response = await axios.put(
-        `${process.env.RADARR_URL}/api/v3/notification/${existingNotification.id}`,
+        `${instance.url}/api/v3/notification/${existingNotification.id}`,
         { ...notificationPayload, id: existingNotification.id },
-        { headers: { 'X-Api-Key': process.env.RADARR_API_KEY } }
+        { headers: { 'X-Api-Key': instance.apiKey } }
       );
       res.json(response.data);
     } else {
       // Create new notification
       const response = await axios.post(
-        `${process.env.RADARR_URL}/api/v3/notification`,
+        `${instance.url}/api/v3/notification`,
         notificationPayload,
-        { headers: { 'X-Api-Key': process.env.RADARR_API_KEY } }
+        { headers: { 'X-Api-Key': instance.apiKey } }
       );
       res.json(response.data);
     }