Function touch_id_sidecar_state 

fn touch_id_sidecar_state(path: &Path) -> Result<TouchIdSidecarState>

Returns the state of the file at path with respect to the Touch ID sidecar schema.

Classification order:

1. Not found → Missing
2. Has both version and crypto/Crypto fields → Keystore
3. Parses strictly as a v1 Touch ID sidecar + plausible payload → Recognized
4. Everything else → Unknown