Fix extension transfer system and browser phone compatibility

Major Fixes:
- Fixed extension transfers going directly to voicemail for available agents
- Resolved browser phone call disconnections during transfers
- Fixed voicemail transcription placeholder text issue
- Added Firefox compatibility with automatic media permissions

Extension Transfer Improvements:
- Changed from active client dialing to proper queue-based system
- Fixed client name generation consistency (user_login vs display_name)
- Added 2-minute timeout with automatic voicemail fallback
- Enhanced agent availability detection for browser phone users

Browser Phone Enhancements:
- Added automatic microphone/speaker permission requests
- Improved Firefox compatibility with explicit getUserMedia calls
- Fixed client naming consistency across capability tokens and call acceptance
- Added comprehensive error handling for permission denials

Database & System Updates:
- Added auto_busy_at column for automatic agent status reversion
- Implemented 1-minute auto-revert system for busy agents with cron job
- Updated database version to 1.6.2 for automatic migration
- Fixed voicemail user_id association for extension voicemails

Call Statistics & Logging:
- Fixed browser phone calls not appearing in agent statistics
- Enhanced call logging with proper agent_id association in JSON format
- Improved customer number detection for complex call topologies
- Added comprehensive debugging for call leg detection

Voicemail & Transcription:
- Replaced placeholder transcription with real Twilio API integration
- Added manual transcription request capability for existing voicemails
- Enhanced voicemail callback handling with user_id support
- Fixed transcription webhook processing for extension voicemails

Technical Improvements:
- Standardized client name generation across all components
- Added ElevenLabs TTS integration to agent connection messages
- Enhanced error handling and logging throughout transfer system
- Fixed TwiML generation syntax errors in dial() methods

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

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

includes/class-twp-core.php

@@ -157,6 +157,7 @@ class TWP_Core {
         $this->loader->add_action('wp_ajax_twp_send_to_voicemail', $plugin_admin, 'ajax_send_to_voicemail');
         $this->loader->add_action('wp_ajax_twp_disconnect_call', $plugin_admin, 'ajax_disconnect_call');
         $this->loader->add_action('wp_ajax_twp_get_transfer_targets', $plugin_admin, 'ajax_get_transfer_targets');
+        $this->loader->add_action('wp_ajax_twp_initialize_user_queues', $plugin_admin, 'ajax_initialize_user_queues');
         
         // Eleven Labs AJAX
         $this->loader->add_action('wp_ajax_twp_get_elevenlabs_voices', $plugin_admin, 'ajax_get_elevenlabs_voices');