Fix dashboard metadata source testing

- Point the dashboard Test Connection button at the active metadata source instead of hardcoded Spotify.
- Populate the response line from the current status payload so the card no longer stays at Response: --.
- Keep the existing Spotify-specific auth handling when Spotify is the configured source.

webui/index.html

@@ -626,7 +626,7 @@
                                 <p class="service-card-response-time" id="spotify-response-time">Response: --</p>
                                 <div class="service-card-footer">
                                     <button class="service-card-button"
-                                        onclick="testDashboardConnection('spotify')">Test Connection</button>
+                                        onclick="testDashboardConnection(getActiveMetadataSource())">Test Connection</button>
                                 </div>
                             </div>
                             <div class="service-card" id="media-server-service-card">

webui/static/core.js

@@ -885,4 +885,8 @@ const API = {
 let _lastServiceStatus = null;
 let _isSoulsyncStandalone = false;  // Global flag: true when no media server (sync buttons hidden)
 
+function getActiveMetadataSource() {
+    return _lastServiceStatus?.spotify?.source || 'spotify';
+}
+
 // ===============================

webui/static/shared-helpers.js

@@ -3323,6 +3323,20 @@ function updateServiceStatus(service, statusData) {
         }
 
         syncPrimaryMetadataSourceAvailability(statusData);
+
+        const responseTimeElement = document.getElementById('spotify-response-time');
+        if (responseTimeElement) {
+            const responseTime = statusData.response_time;
+            responseTimeElement.textContent = responseTime !== undefined && responseTime !== null
+                ? `Response: ${responseTime}ms`
+                : 'Response: --';
+        }
+
+        const testButton = document.querySelector('#spotify-service-card .service-card-button');
+        if (testButton) {
+            const source = statusData.source || 'spotify';
+            testButton.setAttribute('onclick', `testDashboardConnection('${source}')`);
+        }
     }
 
     // Update download source title on dashboard card