Function validate_round_trip_stability 

pub fn validate_round_trip_stability(record: &LnmpRecord) -> bool

Validates that canonicalization is idempotent (round-trip stable)

Verifies that canonicalize(canonicalize(x)) == canonicalize(x) This ensures that the canonicalization process is stable and deterministic.

Returns true if the record is round-trip stable, false otherwise.