pub fn from_value(v: &Value) -> Result<Tick, String>Expand description
Strict parse of an on-disk tick — this IS the R1 (closed schema) + R2 (check shape) check.
Two-tier forward-compat (T3): the hashed/identity set (HASHED_TOP_LEVEL_KEYS) stays STRICT —
a missing one is an Err, and the nested grounds/check schemas reject any unknown key inside the
HASHED payload, so the content-addressed id can never carry an unvalidated field. The known
non-hashed fields are validated. A truly-unknown OTHER top-level key is TOLERATED (parsed
through, not rejected) so a newer writer’s bookkeeping field does not brick an older reader;
ev verify surfaces it as a warning: so a typo’d field name stays visible.