6519582de6
EnsureGitignore writes a minimal .gitignore (.ctask/ +
logs/sessions.log) iff one does not already exist. This is the
file-system half of the v0.3 seed-wins rule for .gitignore: if
either the general or project seed copied a .gitignore into the
workspace, EnsureGitignore must be a no-op.
GitAvailable + RunGitInit wrap exec.LookPath("git") and `git init`
respectively, so the caller in cmd/new.go can decide whether to
print the informational note when git is missing.
Tests cover:
- missing -> created with the minimal body
- present -> preserved verbatim
- integration: general seed .gitignore preserved end-to-end
- integration: project seed .gitignore preserved end-to-end
- integration: no seed -> minimal body created