Update README with Docker deployment instructions and auth features

- Added comprehensive Docker Compose deployment section as recommended method
- Documented automatic database migrations and persistent storage
- Updated architecture section to mention SQLite auth system
- Added new User Experience section highlighting session management
- Reorganized development setup with local database migration instructions

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

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

README.md

@@ -29,6 +29,12 @@ While there are many excellent self-hosted CalDAV server implementations (Nextcl
 - **Real-time Updates**: Seamless synchronization with CalDAV servers
 - **Timezone Aware**: Proper local time display with UTC storage
 
+### User Experience
+- **Persistent Preferences**: Settings sync across devices and sessions
+- **Remember Me**: Optional server/username remembering for convenience
+- **Session Management**: Secure session tokens with automatic expiry
+- **Cross-Device Sync**: User preferences stored in database, not just browser
+
 ## Architecture
 
 ### Frontend (Yew WebAssembly)
@@ -40,7 +46,8 @@ While there are many excellent self-hosted CalDAV server implementations (Nextcl
 
 ### Backend (Axum)  
 - **Framework**: Axum async web framework with CORS support
-- **Authentication**: JWT token management and validation
+- **Authentication**: SQLite-backed session management with JWT tokens
+- **Database**: SQLite for user preferences and session storage
 - **CalDAV Client**: Full CalDAV protocol implementation for server sync
 - **API Design**: RESTful endpoints following calendar operation patterns
 - **Data Flow**: Proxy between frontend and CalDAV servers with proper authentication
@@ -54,12 +61,36 @@ While there are many excellent self-hosted CalDAV server implementations (Nextcl
 
 ## Getting Started
 
-### Prerequisites
+### Docker Deployment (Recommended)
 
+The easiest way to run the calendar is using Docker Compose:
+
+1. **Clone the repository**:
+   ```bash
+   git clone <repository-url>
+   cd calendar
+   ```
+
+2. **Start the application**:
+   ```bash
+   docker compose up
+   ```
+
+3. **Access the application** at `http://localhost`
+
+The Docker setup includes:
+- **Automatic database migrations** on startup
+- **Persistent data storage** in `./data/db/` volume
+- **Frontend served via Caddy** on port 80
+- **Backend API** accessible on port 3000
+
+### Development Setup
+
+#### Prerequisites
 - Rust (latest stable version)
 - Trunk (`cargo install trunk`)
 
-### Development Setup
+#### Local Development
 
 1. **Start the backend server** (serves API at http://localhost:3000):
    ```bash
@@ -73,6 +104,17 @@ While there are many excellent self-hosted CalDAV server implementations (Nextcl
 
 3. **Access the application** at `http://localhost:8080`
 
+#### Database Setup
+
+For local development, run the database migrations:
+```bash
+# Install sqlx-cli if not already installed
+cargo install sqlx-cli --features sqlite
+
+# Run migrations
+sqlx migrate run --database-url "sqlite:calendar.db" --source backend/migrations
+```
+
 ### Building for Production
 
 ```bash