Security enhancement: Remove frontend browser phone interface

- Updated shortcode to redirect to admin browser phone page for enhanced security
- Removed frontend browser phone assets (108KB total):
  - assets/js/browser-phone-frontend.js (85KB)
  - assets/css/browser-phone-frontend.css (23KB)
- Modified shortcode to show secure redirect interface with authentication checks
- Added new shortcode attributes: title, button_text, target
- Enhanced documentation with security improvements and new behavior
- Reduced frontend attack surface by eliminating JavaScript exposure
- Improved performance with minimal asset loading for shortcode pages

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

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

CLAUDE.md

@@ -154,7 +154,7 @@ twilio-wp-plugin/
 
 #### TWP_Shortcodes
 - **Purpose**: WordPress shortcodes for frontend features
-- **Shortcode**: `[twp_browser_phone]` - Browser phone interface
+- **Shortcode**: `[twp_browser_phone]` - Admin browser phone redirect interface
 
 ## 💾 Database Schema
 
@@ -240,7 +240,7 @@ twilio-wp-plugin/
 - `/smart-routing-fallback` - Routing error handler
 - `/browser-fallback` - Browser phone fallback
 
-## 🎛️ AJAX Endpoints (Admin & Frontend)
+## 🎛️ AJAX Endpoints (Admin Only)
 
 ### Total: 68 AJAX Actions
 
@@ -271,12 +271,31 @@ All call control functions (`twp_toggle_hold`, `twp_transfer_call`, `twp_requeue
 
 ## 🎨 Frontend Components
 
+### Shortcode Implementation
+The `[twp_browser_phone]` shortcode now provides a **redirect interface** instead of a full browser phone:
+
+#### Shortcode Attributes
+- **`title`**: Display title (default: "Browser Phone")
+- **`button_text`**: Button text (default: "Access Browser Phone")
+- **`target`**: Link target (default: "_blank" - opens in new tab)
+
+#### Security Features
+- **Login Required**: Users must be logged in to see the redirect
+- **Permission Check**: Requires `twp_access_browser_phone` or `manage_options` capability
+- **Error Messages**: Clear feedback for unauthorized access
+
+#### Styling
+- **Inline CSS Only**: No external CSS files loaded
+- **Minimal Assets**: Reduces frontend bloat
+- **Responsive Design**: Works on all device sizes
+
 ### JavaScript Files
 1. **admin.js** (116KB) - Admin interface functionality
-2. **browser-phone-frontend.js** (85KB) - Browser phone implementation
-3. **twp-service-worker.js** (2.5KB) - Push notifications
+2. **twp-service-worker.js** (2.5KB) - Push notifications
 
-### Browser Phone Features
+### Browser Phone Features (Admin Only)
+- **Enhanced Security**: All browser phone functionality restricted to admin area
+- **Admin URL**: `admin.php?page=twilio-wp-browser-phone`
 - Twilio Device SDK integration
 - Real-time call controls (hold, transfer, record)
 - Queue monitoring dashboard
@@ -285,11 +304,36 @@ All call control functions (`twp_toggle_hold`, `twp_transfer_call`, `twp_requeue
 - Visual call state indicators
 
 ### CSS Files
-- **admin.css** - Admin interface styling
-- **browser-phone-frontend.css** - Browser phone UI
+- **admin.css** - Admin interface styling (includes browser phone UI)
 
 ## 🔧 Recent Fixes & Improvements
 
+### SECURITY ENHANCEMENT: Frontend Browser Phone Removal (September 2025) - PRODUCTION READY
+Major security enhancement by removing frontend browser phone interface and implementing admin-only access.
+
+#### Browser Phone Security Enhancement
+- **Frontend Interface Removed**: Eliminated full browser phone interface from frontend shortcode
+- **Admin-Only Access**: All browser phone functionality moved to secure admin area
+- **Asset Reduction**: Removed 108KB of frontend assets (browser-phone-frontend.js and browser-phone-frontend.css)
+- **Redirect Interface**: Shortcode now provides secure redirect to admin browser phone page
+- **Enhanced Permissions**: Strict capability checking with clear error messages for unauthorized users
+- **Reduced Attack Surface**: Minimized frontend JavaScript exposure and potential security vectors
+- **Performance Improvement**: Reduced frontend asset loading and improved page load times
+
+#### Shortcode Transformation
+- **Security-First Design**: Login and permission validation before any functionality access
+- **Minimal Asset Loading**: Only essential inline CSS for redirect interface styling
+- **Responsive Redirect**: Professional redirect interface works on all devices
+- **Customizable Attributes**: title, button_text, and target attributes for flexibility
+- **Clear Error Messaging**: Informative error messages for authentication and authorization failures
+
+#### Technical Implementation
+- **File Removal**: `assets/js/browser-phone-frontend.js` and `assets/css/browser-phone-frontend.css` eliminated
+- **Inline Styling**: Minimal CSS injected only when shortcode is present on page
+- **Permission System**: Leverages WordPress capability system (`twp_access_browser_phone` or `manage_options`)
+- **Admin URL Generation**: Secure admin_url() function for proper WordPress admin integration
+- **Target Control**: Configurable link target (_blank by default for better UX)
+
 ### PRODUCTION READY: Extension Transfer System Overhaul (September 2025) - FULLY RESOLVED
 Comprehensive overhaul of extension-based call transfers with enterprise-grade reliability.