Add UV run support and systemd service installer

**UV Integration:**
- Updated pyproject.toml with [tool.uv.scripts]
- Added 'uv run start' to launch wedding phone
- Added 'uv run test' to run audio tests
- Refactored main code into main() function
- Added proper entry point for package installation

**Systemd Service:**
- Created wedding-phone.service template
- Service runs with UV for dependency management
- Automatic restart on failure
- Proper security hardening (NoNewPrivileges, PrivateTmp)
- GPIO and audio group access configured

**Service Installer:**
- Created install_service.sh automated installer
- Auto-detects project path and user
- Checks for UV installation and dependencies
- Configures service file with correct paths
- Option to enable and start immediately
- Provides helpful command reference

**Installer Features:**
- Validates config.json exists (creates from example if missing)
- Installs UV dependencies automatically
- Updates service file paths dynamically
- Color-coded output for clarity
- Error checking at each step
- Clean installation process

**Usage:**
```bash
# Run directly with UV
uv run start

# Install as system service
./install_service.sh

# Service management
sudo systemctl start wedding-phone
sudo systemctl stop wedding-phone
sudo journalctl -u wedding-phone -f
```

**Documentation:**
- Updated README with UV commands
- Added service installation guide
- Removed old manual systemd instructions
- Added service management commands
- Updated file structure documentation

**Benefits:**
- Easier to run (single command)
- Automatic startup on boot
- Better dependency management
- Professional service integration
- Simplified installation process

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

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

rotary_phone_web.py

@@ -873,12 +873,13 @@ def get_local_ip():
     except:
         return "127.0.0.1"
 
-if __name__ == "__main__":
+def main():
+    """Main entry point for the wedding phone application"""
     # Create templates directory and HTML template
     script_dir = os.path.dirname(os.path.abspath(__file__))
     templates_dir = os.path.join(script_dir, 'templates')
     os.makedirs(templates_dir, exist_ok=True)
-    
+
     # Create the HTML template if it doesn't exist
     template_file = os.path.join(templates_dir, 'index.html')
     if not os.path.exists(template_file):
@@ -1983,3 +1984,6 @@ if __name__ == "__main__":
     
     # Start Flask web server
     app.run(host='0.0.0.0', port=WEB_PORT, debug=False, threaded=True)
+
+if __name__ == "__main__":
+    main()