Add mobile app infrastructure and Gitea auto-update support

This commit adds comprehensive mobile app support to enable a native Android app that won't timeout or sleep when the screen goes dark.

New Features:
- JWT-based authentication system (no WordPress session dependency)
- REST API endpoints for mobile app (agent status, queue management, call control)
- Server-Sent Events (SSE) for real-time updates to mobile app
- Firebase Cloud Messaging (FCM) integration for push notifications
- Gitea-based automatic plugin updates
- Mobile app admin settings page

New Files:
- includes/class-twp-mobile-auth.php - JWT authentication with login/refresh/logout
- includes/class-twp-mobile-api.php - REST API endpoints under /twilio-mobile/v1
- includes/class-twp-mobile-sse.php - Real-time event streaming
- includes/class-twp-fcm.php - Push notification handling
- includes/class-twp-auto-updater.php - Gitea-based auto-updates
- admin/mobile-app-settings.php - Admin configuration page

Modified Files:
- includes/class-twp-activator.php - Added twp_mobile_sessions table
- includes/class-twp-core.php - Load and initialize mobile classes
- admin/class-twp-admin.php - Added Mobile App menu item and settings page

Database Changes:
- New table: twp_mobile_sessions (stores JWT refresh tokens and FCM tokens)

API Endpoints:
- POST /twilio-mobile/v1/auth/login
- POST /twilio-mobile/v1/auth/refresh
- POST /twilio-mobile/v1/auth/logout
- GET/POST /twilio-mobile/v1/agent/status
- GET /twilio-mobile/v1/queues/state
- POST /twilio-mobile/v1/calls/{call_sid}/accept
- GET /twilio-mobile/v1/stream/events (SSE)

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

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

admin/class-twp-admin.php

@@ -119,7 +119,16 @@ class TWP_Admin {
                 'twilio-wp-settings',
                 array($this, 'display_plugin_settings')
             );
-            
+
+            add_submenu_page(
+                'twilio-wp-plugin',
+                'Mobile App',
+                'Mobile App',
+                'manage_options',
+                'twilio-wp-mobile-app',
+                array($this, 'display_mobile_app_settings')
+            );
+
             add_submenu_page(
                 'twilio-wp-plugin',
                 'Phone Schedules',
@@ -10049,5 +10058,12 @@ class TWP_Admin {
             wp_send_json_error('Failed to accept transfer: ' . $e->getMessage());
         }
     }
-    
+
+    /**
+     * Display mobile app settings page
+     */
+    public function display_mobile_app_settings() {
+        require_once TWP_PLUGIN_DIR . 'admin/mobile-app-settings.php';
+    }
+
 }