After the templates are copied, create-project.sh adds /.claude, /.agents and
/AGENTS.md to .git/info/exclude of the new project as its own step, "Git
excludes". No .gitignore or tracked file changes and nothing is committed.
The step is skipped when the framework steps are skipped, and a path git
already tracks stays tracked and is named in the step.
The .git/info/exclude code of exclude_env_file moves into the shared helper
exclude_from_git (git.sh), which both now use; the .env behavior is unchanged.
Refs #66
Task: MIL-009#2
Tirsvad
4058ab4e3e