pub fn normalize(s: &str) -> Result<String>Expand description
Widen a timestamp to canonical form.
Accepts the canonical form unchanged and the legacy second-precision form
YYYY-MM-DDTHH:MM:SSZ, which is widened by appending .000000. Anything
else — an offset like +01:00, a missing Z, millisecond precision — is
rejected rather than guessed at, because every silent repair here becomes a
wrong answer in a temporal query later.