fix: resolve port configuration issues and database column mismatch

- Fixed database query in adminDashboard.js using non-existent 'created_at' column
  Changed to use 'scheduled_at' for email_queue table queries
- Updated frontend/.env.example to default to Docker configuration (port 3001/api)
- Clarified DEPLOYMENT_GUIDE.md with separate frontend/backend configuration sections
- Added explicit port configuration warnings to prevent future mismatches
- Added beta features section to README for download protection and deployment script

The 500 errors were caused by:
1. Frontend .env pointing to wrong port (3002 instead of 3001)
2. Database query using 'created_at' instead of 'scheduled_at' for email_queue

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

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

README.md

@@ -40,6 +40,7 @@ Unlike expensive SaaS solutions, PicPeak gives you:
 - ⬇️ **Bulk Downloads** - Download all photos with one click
 - 🔍 **Smart Search** - Find photos quickly
 - 📤 **Guest Uploads** - Optional client photo uploads
+- 🛡️ **Download Protection** - Advanced image protection with watermarking and right-click prevention
 
 ### Technical Excellence
 - 🐳 **Docker Ready** - Deploy in minutes
@@ -177,6 +178,17 @@ Organize and manage your photo galleries with intuitive event management tools.
 
 We're constantly improving PicPeak and welcome contributions from our community! If you have ideas for new features or want to help implement existing ones, please open an issue or submit a pull request. Your contributions help make PicPeak better for everyone.
 
+### 🚧 Beta Features (Use at your own risk)
+
+These features are currently in beta testing and may have limited functionality or stability:
+
+| Feature | Description | Status |
+|---------|-------------|--------|
+| **Download Protection** | Advanced image protection system with canvas rendering, invisible watermarking, and right-click prevention to protect your photos from unauthorized downloads | 🧪 Beta |
+| **Simple Deployment Script** | One-click deployment script for quick server setup with automated configuration and dependency installation | 🧪 Beta |
+
+### 📋 Future Enhancements
+
 | Feature | Description | Priority | Status |
 |---------|-------------|----------|---------|
 | **Backup & Restore** | Comprehensive backup system with S3/MinIO support, automated scheduling, and safe restore functionality | High | ✅ Implemented |