pub fn decode_cwd_dirname(name: &str) -> Option<PathBuf>Expand description
Decode a session-directory name back to the cwd it encodes, or None for a
hash-fallback name (recover via the .cwd sidecar) or a malformed escape.
Only names starting with + decode — an encoded absolute path always starts with
+ (the leading /), and a fallback name starts with a hex digit, so the first
byte disambiguates the two forms.