pub fn validate_command_token(command: &str) -> Result<(), String>Expand description
Validate a stdio command as a single executable token.
Accepts either a bare executable name (no /, \, or whitespace, resolved
via platform search) or a plugin-relative ./ path (resolved against the
plugin root; spaces allowed since spawn is argv-based). Rejects empty
values, bare directory tokens (./, ./.), NUL/newlines, and
shell-control characters so a shell command string can never slip through
as one token (Agent Plugins ยง7.2.1: single token, bare or ./).