Add copilot helper files.

.github/copilot-instructions.md

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+# GSmartControl – Copilot Instructions
+
+GSmartControl is a C++20 GTK3/Gtkmm GUI for inspecting hard-drive and SSD health via SMART data
+(wrapping `smartctl` from smartmontools). It supports Linux, Windows (MSYS2/MinGW), macOS, and BSDs.
+
+## Build
+
+```bash
+mkdir build && cd build
+
+# Standard Linux build (uses dev toolchain with warnings enabled)
+cmake .. -DCMAKE_BUILD_TYPE=RelWithDebInfo \
+         -DCMAKE_TOOLCHAIN_FILE=../toolchains/linux-dev.cmake
+
+# Windows (MSYS2/MinGW64)
+cmake .. -G "MSYS Makefiles" \
+         -DCMAKE_BUILD_TYPE=RelWithDebInfo \
+         -DCMAKE_TOOLCHAIN_FILE=../toolchains/win64-mingw-msys2.cmake
+
+cmake --build . --config RelWithDebInfo
+```
+
+The `configure-dev` script is a convenience wrapper: `./configure-dev -t <toolchain> -c <compiler> -b <build_type>`.
+
+Key CMake options:
+- `-DAPP_BUILD_TESTS=ON` – enable test targets
+- `-DAPP_BUILD_EXAMPLES=ON` – enable example targets
+- `-DAPP_COMPILER_ENABLE_WARNINGS=ON` – strict compiler warnings (set automatically by `linux-dev.cmake`)
+
+## Tests
+
+Tests use **Catch2** (vendored in `dependencies/catch2/`). They are only built when `-DAPP_BUILD_TESTS=ON` is passed.
+
+```bash
+# Build and run all tests
+cmake .. -DAPP_BUILD_TESTS=ON
+cmake --build .
+ctest -C RelWithDebInfo --rerun-failed --output-on-failure
+
+# Run a single test executable directly (from build dir)
+./test_all "[smartctl_parser]"        # Catch2 tag filter
+./test_all "test name substring"      # substring match
+```
+
+Test sources live in `src/applib/tests/` and `src/hz/tests/`; they are linked into `src/test_all/`.
+
+## Linting
+
+Clang-tidy config is at `.clang-tidy` in the repo root. Run it via CMake or directly:
+
+```bash
+clang-tidy src/applib/storage_device.cpp -- -std=c++20 $(pkg-config --cflags gtkmm-3.0)
+```
+
+## Architecture
+
+The codebase is split into libraries and one GUI executable:
+
+| Component | Location | Purpose |
+|---|---|---|
+| `applib` | `src/applib/` | Core logic: SMART parsing, device detection, command execution |
+| `hz` | `src/hz/` | General-purpose C++ utilities (strings, filesystem, error types) |
+| `rconfig` | `src/rconfig/` | Runtime config load/save with auto-save support |
+| `libdebug` | `src/libdebug/` | Debug logging with named channels |
+| `gui` | `src/gui/` | GTK/Gtkmm UI (windows, dialogs, Glade `.ui` files) |
+
+### Parsing pipeline
+
+`smartctl` output is parsed through a strategy pattern:
+- JSON parsers (`smartctl_json_ata_parser`, `smartctl_json_nvme_parser`, `smartctl_json_basic_parser`) target smartctl ≥ 7.3.
+- Text parsers (`smartctl_text_ata_parser`, `smartctl_text_basic_parser`) handle legacy output.
+- Parsed results are stored as `StorageProperty` objects in a `StoragePropertyRepository` on `StorageDevice`.
+
+### Device detection
+
+`StorageDetector` is an abstract interface; platform implementations are:
+- `storage_detector_linux.cpp` – scans `/dev/sd*`, `/dev/nvme*`, etc.
+- `storage_detector_win32.cpp` – WMI/registry enumeration
+- `storage_detector_other.cpp` – generic `/dev` scanning (BSD/macOS)
+
+### Async execution
+
+`AsyncCommandExecutor` wraps `CommandExecutor` (which shells out to `smartctl`) in a background thread. 
+Completion is signalled via **libsigc++** signals back to the GTK main loop. Never call GTK APIs from the worker thread;
+queue them through signals or `Glib::signal_idle()`.
+
+### Error handling
+
+Use `hz::ExpectedValue<T, E>` (wrapping `tl::expected`) for recoverable errors instead of exceptions. 
+Enum-based error types (`StorageDeviceError`, `SmartctlParserError`) are preferred over string errors.
+
+## Key Conventions
+
+**Naming:**
+- Classes: `PascalCase` (e.g., `StorageDevice`, `SmartctlParser`)
+- Methods and members: `snake_case`; private/member fields have a trailing `_` (e.g., `device_list_`)
+- GUI classes in `src/gui/` are prefixed `Gsc` (e.g., `GscMainWindow`)
+- Filenames: `snake_case.cpp` / `snake_case.h`
+
+**Headers:**
+- Use `#ifndef FILENAME_H` / `#define FILENAME_H` guards (not `#pragma once`)
+- Include order: standard library → third-party (GTK/Gtkmm) → project headers
+- All project headers are included relative to `src/` (the include root)
+
+**Modern C++20/23 patterns used throughout:**
+- `std::optional<T>` for nullable values
+- `hz::ExpectedValue<T, E>` for error-returning functions
+- `std::string_view` for non-owning string parameters
+- `fmt::format()` (vendored `fmt` library) for string formatting
+- Smart pointers exclusively; no raw owning pointers
+
+**Vendored dependencies** are in `dependencies/` and added via `add_subdirectory`.
+Do not modify them; prefer upgrading the whole vendored copy.
+
+**Translations:** UI strings are wrapped with `_()` (gettext). `.po` files live in `po/`.
+Translations are not yet supported.
+
+**Platform guards:** Use `#ifdef CONFIG_KERNEL_FAMILY_WINDOWS`, 
+`#ifdef CONFIG_KERNEL_LINUX`, etc.
+
+## Agentic Development
+
+Place all plans and temporary files in `agent_workspace/`. This directory is ignored by Git.