Implement bridged forwarding with agent call control features

Major enhancement to workflow forwarding that solves voicemail issues and adds agent call control capabilities.

Key improvements:
- Converted direct forwarding to bridged forwarding to avoid self-call voicemail issues
- Added DTMF-based agent features during calls:
  * *9 - Hold/Unhold customer
  * *0 - Start/Stop call recording
  * *5 - Transfer to another extension
  * *1 - Mute/Unmute (placeholder for future conference mode)
- Added webhook handlers for agent features and forward results
- Agent features URL attached to Number elements for DTMF detection
- Continuous DTMF listening during active calls
- Proper call leg detection for hold/resume operations

Technical details:
- Added /agent-features webhook for DTMF capture
- Added /agent-action webhook for processing commands
- Added /forward-result webhook for handling dial outcomes
- Modified append_twiml_element to preserve Number attributes (url, method)
- Enhanced logging throughout for debugging

This eliminates the issue where calling yourself would go straight to voicemail and provides professional call control features for agents.

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

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

twilio-wp-plugin.php

@@ -3,7 +3,7 @@
  * Plugin Name: Twilio WP Plugin
  * Plugin URI: https://repo.anhonesthost.net/wp-plugins/twilio-wp-plugin
  * Description: WordPress plugin for Twilio integration with phone scheduling, call forwarding, queue management, and Eleven Labs TTS
- * Version: 2.2.0
+ * Version: 2.8.9
  * Author: Josh Knapp
  * License: GPL v2 or later
  * Text Domain: twilio-wp-plugin
@@ -15,7 +15,7 @@ if (!defined('WPINC')) {
 }
 
 // Plugin constants
-define('TWP_VERSION', '2.8.6');
+define('TWP_VERSION', '2.8.9');
 define('TWP_DB_VERSION', '1.6.2'); // Track database version separately
 define('TWP_PLUGIN_DIR', plugin_dir_path(__FILE__));
 define('TWP_PLUGIN_URL', plugin_dir_url(__FILE__));