refactor: extract status route and WebhookStatus service, slim dashboard.js

- Extract /status route to server/routes/status.js
- Create server/services/WebhookStatus.js with checkWebhookConfigured and aggregateMetrics
- Slim dashboard.js to pure HTTP orchestration (559→283 lines, 49.4% reduction)
- Remove /user-summary and /webhook-metrics routes from dashboard.js
- Mount status router at /api/status in server/index.js and server/app.js
- Update tests to use new /api/status/status endpoint
- Fix test expectation for speed field (number vs string)

All 571 tests passing.

server/services/WebhookStatus.js

@@ -0,0 +1,55 @@
+// Copyright (c) 2026 Gordon Bolton. MIT License.
+const axios = require('axios');
+const { getSonarrInstances, getRadarrInstances } = require('../utils/config');
+
+/**
+ * Check if Sofarr webhook is configured in a Sonarr/Radarr instance.
+ * @param {Object} instance - The Sonarr/Radarr instance config
+ * @param {string} type - 'Sonarr' or 'Radarr'
+ * @returns {Promise<boolean>} true if webhook is configured
+ */
+async function checkWebhookConfigured(instance, type) {
+  try {
+    const response = await axios.get(`${instance.url}/api/v3/notification`, {
+      headers: { 'X-Api-Key': instance.apiKey },
+      timeout: 5000
+    });
+    const notifications = response.data || [];
+    return notifications.some(n => n.name === 'Sofarr' && n.implementation === 'Webhook');
+  } catch (err) {
+    console.log(`[WebhookStatus] Failed to check ${type} webhook config: ${err.message}`);
+    return false;
+  }
+}
+
+/**
+ * Aggregate webhook metrics for a service type.
+ * @param {Object} metricsMap - Map of instance URLs to their metrics
+ * @param {boolean} configured - Whether the service is configured
+ * @returns {Object|null} Aggregated metrics or null if not configured
+ */
+function aggregateMetrics(metricsMap, configured) {
+  const values = Object.values(metricsMap);
+  if (values.length === 0) {
+    // Return default metrics if configured but no events yet
+    return configured ? {
+      enabled: true,
+      eventsReceived: 0,
+      pollsSkipped: 0,
+      lastEvent: null
+    } : null;
+  }
+  return {
+    enabled: true,
+    eventsReceived: values.reduce((sum, m) => sum + (m.eventsReceived || 0), 0),
+    pollsSkipped: values.reduce((sum, m) => sum + (m.pollsSkipped || 0), 0),
+    lastEvent: values.reduce((latest, m) => {
+      return m.lastWebhookTimestamp > latest ? m.lastWebhookTimestamp : latest;
+    }, 0)
+  };
+}
+
+module.exports = {
+  checkWebhookConfigured,
+  aggregateMetrics
+};