fix: stop is_wsl false-positiving in Docker on a WSL2 host

[bushidocodes]

Problem

A Docker container shares the host kernel, so on a WSL2 host /proc/version inside the container also contains "microsoft" and is_wsl() returned true. On every shell start that triggered init_node -> remove_win_node_from_path -> get_win_c_path -> wslpath, which doesn't exist in the container:

/root/.dotfiles/utils.sh: line 33: wslpath: command not found

(plus bogus Explorer.exe/clip.exe aliases). Non-fatal, but noisy and wrong.

Fix

Keep the kernel check, but also require a WSL-only interop marker:

is_wsl() {
    grep -qi microsoft /proc/version || return 1
    [ -n "${WSL_DISTRO_NAME:-}" ] || [ -e /run/WSL ] || command -v wslpath >/dev/null 2>&1
}

Real WSL2 has all three markers; a container on a WSL2 host has none.

Verification (container running on a WSL2 host)

plain container (no markers)        -> is_wsl FALSE   (fixed)
WSL_DISTRO_NAME set                 -> is_wsl TRUE    (no regression)
/run/WSL exists                     -> is_wsl TRUE
wslpath on PATH                     -> is_wsl TRUE
get_win_c_path                      -> exits clean, no wslpath error

Fixes #50

🤖 Generated with Claude Code