chore: add Copilot instructions (#3074)

Author: marcnause

.github/copilot-instructions.md

@@ -0,0 +1,62 @@
+# Project Overview
+
+**PSLab App** is a Flutter cross-platform application for performing
+scientific experiments with the Pocket Science Lab (PSLab) open-hardware
+platform. It provides instruments like oscilloscope, multimeter, wave
+generator, logic analyzer, and various sensor interfaces.
+
+## Tech Stack
+
+- **Framework**: Flutter (stable channel)
+- **Language**: Dart
+- **State Management**: Provider pattern
+- **Dependency Injection**: GetIt (service locator pattern)
+- **Supported Platforms**: Android (primary), iOS, Linux, macOS, Windows, Web
+
+## Repository Structure
+
+```text
+pslab-app/
+├── android/          # Android-specific platform code
+├── ios/              # iOS-specific platform code  
+├── linux/            # Linux-specific platform code
+├── macos/            # macOS-specific platform code
+├── windows/          # Windows-specific platform code
+├── web/              # Web-specific platform code
+├── lib/              # Code shared by all platforms
+│   ├── communication/    # Hardware communication layer (USB, sensors, peripherals)
+│   ├── providers/        # State management (Provider pattern, ~32 files)
+│   ├── view/            # UI screens and widgets
+│   ├── models/          # Data models
+│   ├── theme/           # App theming and colors
+│   ├── l10n/            # Localization (i18n) files
+│   ├── others/          # Utilities and helpers
+│   ├── constants.dart   # App-wide constants
+│   └── main.dart        # App entry point
+├── test/            # Unit tests
+├── test_integration/# Integration tests
+├── assets/          # Images, icons, and other assets
+├── .github/
+│   ├── workflows/   # CI/CD workflows
+│   └── actions/     # Reusable GitHub Actions
+├── scripts/         # Build and deployment scripts
+└── pubspec.yaml     # Dependencies and project configuration
+```
+
+## Coding Standards
+
+- Adhere to the coding style described in <https://dart.dev/effective-dart/style>.
+- Adhere to the SOLID design principles described in <https://simple.wikipedia.org/wiki/SOLID_(object-oriented_design)>.
+- Adhere to Object-Oriented Design best practices described in <http://butunclebob.com/ArticleS.UncleBob.PrinciplesOfOod>.
+- Keep in mind the architecture recommendations described in <https://docs.flutter.dev/app-architecture/guide>.
+
+## Commit Style
+
+- Adhere to the commit style described in the file `commitstyle.md` in
+the `docs` folder of this project.
+
+## UI guidelines
+
+- The UI of the app must be consistent
+- The UI of the app should adhere to the best practices for adaptive design described
+in <https://docs.flutter.dev/ui/adaptive-responsive/best-practices>.