Enhance browser phone with real-time updates and audible alerts

- Fix token expiration: Extend refresh buffer to 10 minutes for reliability
- Add real-time queue updates: Reduce polling to 5 seconds for instant feedback
- Implement audible alert system: 30-second repeating notifications with user toggle
- Optimize Discord/Slack notifications: Non-blocking requests for immediate delivery
- Add persistent alert preferences: Toggle button with localStorage integration
- Clean up debug file: Remove unused debug-phone-numbers.php

🤖 Generated with [Claude Code](https://claude.ai/code)

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

includes/class-twp-notifications.php

@@ -347,12 +347,14 @@ class TWP_Notifications {
      * Send webhook request
      */
     private static function send_webhook_request($webhook_url, $payload, $service) {
+        // Send notification immediately without blocking
         $response = wp_remote_post($webhook_url, array(
             'headers' => array(
                 'Content-Type' => 'application/json',
             ),
             'body' => json_encode($payload),
-            'timeout' => 30,
+            'timeout' => 10, // Reduce timeout for faster processing
+            'blocking' => false, // Non-blocking request for immediate processing
         ));
 
         if (is_wp_error($response)) {
@@ -360,15 +362,9 @@ class TWP_Notifications {
             return false;
         }
 
-        $response_code = wp_remote_retrieve_response_code($response);
-        if ($response_code >= 200 && $response_code < 300) {
-            error_log("TWP {$service} notification sent successfully");
-            return true;
-        } else {
-            error_log("TWP {$service} notification failed with response code: " . $response_code);
-            error_log("Response body: " . wp_remote_retrieve_body($response));
-            return false;
-        }
+        // For non-blocking requests, we can't check response code immediately
+        error_log("TWP {$service} notification sent (non-blocking)");
+        return true;
     }
 
     /**