Add CLAUDE.md with project guidance for Claude Code

Signed-off-by: Mykola Solianko <mykola_solianko@epam.com>

Author: Mykola Solianko

CLAUDE.md

@@ -0,0 +1,80 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+aos_core_lib_cpp is a C++17 library for the Aos Edge platform, providing Control Manager (cm),
+Service Manager (sm), Identity & Access Management (iam), and shared utilities (common).
+
+## Build Commands
+
+```bash
+# Build (Debug by default)
+./build.sh build
+./build.sh build --build-type Release
+./build.sh build --clean          # clean rebuild
+
+# Run all tests
+./build.sh test
+
+# Run a single test binary directly
+./build/bin/<test_name>
+# Or with gtest filter:
+./build/bin/<test_name> --gtest_filter="TestSuite.TestName"
+
+# Code coverage (requires lcov 2.0+)
+./build.sh coverage
+
+# Static analysis
+./build.sh lint
+
+# Generate docs
+./build.sh doc
+```
+
+## Build System
+
+- CMake 3.23+ with Conan package manager for dependencies (GTest 1.14.0, OpenSSL 3.2.1)
+- Key CMake options: `WITH_TEST`, `WITH_COVERAGE`, `WITH_DOC`
+- Custom CMake functions in `cmake/AddModule.cmake`: `add_module()`, `add_test()`, `add_exec()`
+- Compiler flags: `-Wall -Werror -Wextra -Wpedantic`
+
+## Code Architecture
+
+```text
+src/core/
+├── cm/       # Control Manager - orchestration (alerts, launcher, imagemanager, etc.)
+├── sm/       # Service Manager - service lifecycle (launcher, resourcemanager, etc.)
+├── common/   # Shared utilities (crypto, logging, monitoring, types, tools, ocispec, etc.)
+└── iam/      # Identity & Access Management
+```
+
+- **Interface-driven design**: Interfaces live in `*/itf/` subdirs and use `*Itf` suffix with pure virtual methods
+- **Error handling**: Custom `Error` type, not exceptions.
+  Pattern: `if (!err.IsNone()) { return err; }` with `AOS_ERROR_WRAP(err)` for context
+- **Crypto abstraction**: Dual OpenSSL and mbed TLS backends via conditional compilation
+- **Custom containers**: `StaticArray`, `StaticString`, `Array`, `String` instead of STL;
+  `UniquePtr` for smart pointers
+
+## Testing
+
+- Google Test + Google Mock in `*/tests/` subdirectories within each module
+- Mocks in `*/tests/mocks/` (use `MOCK_METHOD`), stubs in `*/tests/stubs/`
+- Integration tests in `src/core/{cm,sm}/tests/`
+- Test config constants in `src/core/testconfig.hpp`
+
+## Coding Conventions
+
+- **Formatting**: WebKit-based clang-format, 120 char line limit
+- **Header guards**: `#ifndef AOS_CORE_<PATH>_HPP_` / `#define` / `#endif`
+- **Namespaces**: nested `aos::sm::launcher`, `aos::core::cm`, etc.
+- **Naming**: `m` prefix for members (`mGroups`), `c` prefix for constants (`cMaxNumGroups`),
+  `Itf` suffix for interfaces, `Mock` suffix for mocks
+- **License header**: All files require SPDX Apache-2.0 header with EPAM copyright
+- **Module CMakeLists**: Follow the pattern using `add_module()` / `add_test()` from `cmake/AddModule.cmake`
+
+## CI Checks
+
+GitHub Actions runs on push/PR: Debug build + test, Release build,
+clang-format + cmake-format + markdownlint checks, cppcheck lint, SonarQube analysis.