Port of upstream grok-build 1.0.4/1.0.5. Two paths read $HOME only, which is usually unset on Windows outside Git Bash: - the global-gitignore fallback (prompt/ignore.rs) now uses std::env::home_dir(), the crate-wide idiom; - fast-worktree's resolve_kigi_home falls back to std::env::home_dir() with the same dunce canonicalization, eliminating the documented divergence from kigi_config::default_kigi_home. On Unix home_dir() reads $HOME first, so behavior is unchanged where HOME is set. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01KSy9S31pZNWXtRZNVJ1sDf