fix(downloads): Fix SABnzbd/qBittorrent collision and webhook metrics

1. Fixed download client collision:
   - SABnzbd client with id 'i3omb' was being overwritten by qBittorrent
   - Now uses unique key ':' like the arr retrievers

2. Fixed webhook metrics showing 0:
   - instanceName from webhooks is generic ('Sonarr', 'Radarr')
   - Not the configured instance name ('i3omb')
   - Now updates metrics for ALL instances of that type

server/routes/webhook.js

@@ -247,10 +247,14 @@ router.post('/sonarr', webhookLimiter, (req, res) => {
     logToFile(`[Webhook] Sonarr payload: ${JSON.stringify(req.body)}`);
 
     // Phase 5.1: update webhook metrics for polling optimization
+    // Note: instanceName from webhook is often generic (e.g., "Sonarr"), not the configured name
+    // Update metrics for all Sonarr instances since we can't reliably match
     const sonarrInstances = getSonarrInstances();
-    const instance = sonarrInstances.find(i => i.name === instanceName);
-    if (instance) {
-      cache.updateWebhookMetrics(instance.url);
+    if (sonarrInstances.length > 0) {
+      for (const inst of sonarrInstances) {
+        cache.updateWebhookMetrics(inst.url);
+      }
+      logToFile(`[Webhook] Updated metrics for ${sonarrInstances.length} Sonarr instance(s)`);
     }
 
     // Phase 2: background cache refresh + SSE broadcast (fire-and-forget)
@@ -296,10 +300,14 @@ router.post('/radarr', webhookLimiter, (req, res) => {
     logToFile(`[Webhook] Radarr payload: ${JSON.stringify(req.body)}`);
 
     // Phase 5.1: update webhook metrics for polling optimization
+    // Note: instanceName from webhook is often generic (e.g., "Radarr"), not the configured name
+    // Update metrics for all Radarr instances since we can't reliably match
     const radarrInstances = getRadarrInstances();
-    const instance = radarrInstances.find(i => i.name === instanceName);
-    if (instance) {
-      cache.updateWebhookMetrics(instance.url);
+    if (radarrInstances.length > 0) {
+      for (const inst of radarrInstances) {
+        cache.updateWebhookMetrics(inst.url);
+      }
+      logToFile(`[Webhook] Updated metrics for ${radarrInstances.length} Radarr instance(s)`);
     }
 
     // Phase 2: background cache refresh + SSE broadcast (fire-and-forget)

server/utils/downloadClients.js

@@ -63,8 +63,9 @@ class DownloadClientRegistry {
         }
 
         const client = new ClientClass(config);
-        this.clients.set(config.id, client);
-        logToFile(`[DownloadClientRegistry] Created ${config.type} client: ${config.name} (${config.id})`);
+        const uniqueKey = `${config.type}:${config.id}`;
+        this.clients.set(uniqueKey, client);
+        logToFile(`[DownloadClientRegistry] Created ${config.type} client: ${config.name} (${uniqueKey})`);
       } catch (error) {
         logToFile(`[DownloadClientRegistry] Failed to create client ${config.id}: ${error.message}`);
       }