ci : add copilot-instructions.md (#15286)

ci : add copilot-instructions.md (#15286)

* Initial plan

* Initialize copilot instructions exploration

* Add comprehensive .github/copilot-instructions.md file

* Update Python environment and tools directory documentation

- Add instructions for using .venv Python environment
- Include flake8 and pyright linting tools from virtual environment
- Add tools/ as core directory in project layout
- Reference existing configuration files (.flake8, pyrightconfig.json)

* add more python dependencies to .venv

* Update copilot instructions: add backend hardware note and server testing

* Apply suggestions from code review

* Apply suggestions from code review

* Replace clang-format with git clang-format to format only changed code

* Minor formatting improvements: remove extra blank line and add trailing newline

* try installing git-clang-format

* try just clang-format

* Remove --binary flag from git clang-format and add git-clang-format installation to CI

* download 18.x release

* typo--

* remove --binary flag

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Co-authored-by: Sigbjørn Skjæret <redacted>