Implement Discord and Slack notifications for call events

Settings & Configuration:
- Added Discord webhook URL, Slack webhook URL settings in admin
- Added notification type toggles (incoming calls, queue timeouts, missed calls)
- Added queue timeout threshold setting (30-1800 seconds)
- Registered all new settings with WordPress options system

Notification System:
- Created TWP_Notifications class for Discord/Slack webhook handling
- Rich message formatting with embeds/attachments for both platforms
- Color-coded notifications (blue=incoming, yellow=timeout, red=missed)
- Comprehensive error handling and logging

Integration Points:
- Incoming calls: Notifications sent when calls enter queues
- Queue timeouts: Automated monitoring via cron job (every minute)
- Missed calls: Notifications for browser phone and general missed calls
- Added notified_timeout column to prevent duplicate timeout notifications

Features:
- Professional Discord embeds with fields and timestamps
- Slack attachments with proper formatting and colors
- Automatic cron job setup for queue timeout monitoring
- Fallback to SMS notifications while Discord/Slack also work
- Configurable notification types and timeout thresholds

This provides real-time call notifications to Discord channels and Slack channels,
helping teams stay informed about incoming calls and queue issues even when
SMS notifications aren't working due to validation delays.

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

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

includes/class-twp-webhooks.php

@@ -338,6 +338,15 @@ class TWP_Webhooks {
      * Send SMS notification to agents about missed browser call
      */
     private function send_agent_notification_sms($customer_number, $twilio_number) {
+        // Send Discord/Slack notification for missed browser call
+        require_once dirname(__FILE__) . '/class-twp-notifications.php';
+        TWP_Notifications::send_call_notification('missed_call', array(
+            'type' => 'missed_call',
+            'caller' => $customer_number,
+            'queue' => 'Browser Phone',
+            'workflow_number' => $twilio_number
+        ));
+        
         // Get agents with phone numbers
         $agents = get_users(array(
             'meta_key' => 'twp_phone_number',
@@ -556,6 +565,15 @@ class TWP_Webhooks {
      * Send SMS notification to agents about missed call
      */
     private function send_missed_call_notification($customer_number, $twilio_number) {
+        // Send Discord/Slack notification for missed call
+        require_once dirname(__FILE__) . '/class-twp-notifications.php';
+        TWP_Notifications::send_call_notification('missed_call', array(
+            'type' => 'missed_call',
+            'caller' => $customer_number,
+            'queue' => 'General',
+            'workflow_number' => $twilio_number
+        ));
+        
         // Get agents with phone numbers
         $agents = get_users(array(
             'meta_key' => 'twp_phone_number',