Function append_shadow_validate_log

atomic-cli/src/commands/git/shadow.rs:353–360

Append a `shadow-validate: ` entry to `.atomic/hook-errors.log` (SPEC §6.5) so a non-interactive shadow push that a Validator rule aborts leaves a durable, greppable trail instead of failing silently.

(repo_root: &Path, rule: &str, view: &str, detail: &str)

/// §6.5) so a non-interactive shadow push that a Validator rule aborts leaves a
/// durable, greppable trail instead of failing silently.
pub(crate) fn append_shadow_validate_log(repo_root: &Path, rule: &str, view: &str, detail: &str) {
    append_shadow_log(
        repo_root,
        &format!("shadow-validate:{}", rule),
        view,
        detail,
    );
}

/// Append one tagged `.atomic/hook-errors.log` line. Best-effort: log I/O errors
/// are ignored (the operation already surfaces its own outcome).