Function resolve_transcript 

pub fn resolve_transcript(
    host: HostKind,
    cwd: &Path,
) -> Result<Option<PathBuf>, ResolveError>

Resolve the most-recently-modified transcript file for the given host + cwd. When host == HostKind::Auto, walks every supported host’s candidate set and returns the global most-recent.

Returns Ok(None) (not an Err) when no transcript is located for any supported host — this is a legitimate steady-state on a fresh dev box where no AI agent has ever written a transcript.

Errors

Currently never errors at the resolver level; the underlying filesystem walk surfaces I/O issues via empty-candidate fallthrough. The signature reserves the error arm for future host adapters that perform stricter validation.