revised README structure

README.md

@@ -18,22 +18,23 @@ Pi Zero 2W + Arduino Nano motorcycle info terminal.
 
 ```
 smart-serow/
-├── arduino/              # Arduino sketches
-│   └── hello.ino
+├── arduino/                # Arduino sketches (sensor interface)
+├── extra/                  # Assets deployed alongside app
+│   ├── fonts/              # Custom fonts
+│   ├── images/             # Static images
+│   └── themes/             # Theme JSON files (→ generate_theme.py)
 ├── pi/
-│   └── ui/               # Flutter app (elinux target)
-│       ├── lib/main.dart
-│       ├── pubspec.yaml
-│       └── elinux/       # Generated by flutter-elinux (gitignored)
-├── scripts/
-│   ├── build.py          # Cross-compile for ARM64
-│   ├── deploy.py         # Push to Pi via rsync
-│   ├── build-deploy.py   # One-click build + deploy
-│   ├── deploy_target.sample.json
-│   ├── pi_setup.sh       # One-time Pi setup
-│   └── smartserow-ui.service.sample
-├── pi_sysroot/           # Pi libraries for cross-linking (gitignored)
-└── LICENSE
+│   └── ui/                 # Flutter app
+│       ├── lib/
+│       │   ├── main.dart           # Entry point
+│       │   ├── app_root.dart       # Screen state management
+│       │   ├── screens/            # Full-screen views
+│       │   ├── widgets/            # Reusable components
+│       │   ├── services/           # Singletons (config, sensors, theme)
+│       │   └── theme/              # Colors and theme provider
+│       └── config.json             # Runtime config (navigator, paths)
+├── scripts/                # Build, deploy, and setup helpers
+└── pi_sysroot/             # Pi libraries for cross-linking (gitignored)
 ```
 
 ## Theme System