Fix APRS observer location not updating after settings change

Dispatch observer-location-changed event from settings manager and
listen for it in APRS mode so manual location saves propagate to
the map and distance calculations. Also refresh ObserverLocation in
initAprsMap() to catch changes between page load and first map use.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

static/js/core/settings-manager.js

@@ -1090,6 +1090,14 @@ async function saveObserverLocation() {
         SSTV.loadIssSchedule();
     }
 
+    // Update APRS user location if function is available
+    if (typeof updateAprsUserLocation === 'function') {
+        updateAprsUserLocation({ latitude: lat, longitude: lon });
+    }
+
+    // Notify all listeners (any mode can subscribe)
+    window.dispatchEvent(new CustomEvent('observer-location-changed', { detail: { lat, lon } }));
+
     if (typeof showNotification === 'function') {
         showNotification('Location', notificationMessage);
     }