Use pixi instead of conda

[johnstairs]

Migrating environment management from conda to pixi. Also skipping MATLAB installation on ARM64.

[Copilot]

Pull request overview

Migrates the repository’s environment management from conda (environment.yml) to pixi (pixi.toml/pixi.lock), updating CI and the devcontainer to provision dependencies via Pixi and adding an option to skip MATLAB installation on ARM64.

Changes:

• Replace environment.yml with Pixi workspace config (pixi.toml) and lockfile (pixi.lock), update docs/README accordingly.
• Update GitHub Actions to use a new configure-environment composite action that sets up Pixi and Go using tooling/go.mod.
• Rework devcontainer provisioning to install Pixi in the image and create the Pixi env in a persisted .pixi volume; add conditional MATLAB install and new post-* hooks.

Reviewed changes

Copilot reviewed 16 out of 18 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tooling/go.mod	Updates Go version used by CI/devcontainer tooling installs.
README.md	Updates developer setup docs to reference Pixi instead of Conda.
pyrightconfig.json	Expands Pyright excludes (node_modules, caches, dotdirs).
pixi.toml	Defines Pixi workspace deps and a dev feature for local tooling.
pixi.lock	Locks Pixi/conda package resolution for reproducible installs.
justfile	Adds build dir cleaning and build-type-aware CMake configure recipes.
environment.yml	Removes old Conda environment definition.
docs/cpp/installation.md	Adds Pixi-based dependency installation guidance; keeps Conda alternative.
cpp/CMakeLists.txt	Adjusts debug flags (adds -U_FORTIFY_SOURCE).
.vscode/c_cpp_properties.json	Points VS Code C++ compiler path at Pixi-provided toolchain.
.gitignore	Ignores .pixi/ (Pixi env/cache directory).
.github/workflows/ci.yml	Switches CI to the new Pixi-based environment configuration.
.github/actions/configure-environment/action.yml	Implements Pixi+Go setup for CI jobs.
.devcontainer/Dockerfile	Replaces Conda install with Pixi install; makes MATLAB install conditional and skips on ARM64.
.devcontainer/devcontainer.json	Adds Pixi volume mount and post-create/start hooks; updates tool paths to Pixi env.
.devcontainer/devcontainer.bashrc	Activates Pixi dev environment for interactive shells.
.devcontainer/devcontainer-post-start.sh	Ensures .bashrc sources the devcontainer bashrc after dotfiles apply.
.devcontainer/devcontainer-post-create.sh	Creates the Pixi dev env, stable tool symlinks, and CMake Tools kits file.

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[naegelejd]

Hooray 💯 🥳