Add ToJSON instance for new experimental TxOut
Implement ToJSON for the new TxOut type that wraps L.TxOut era, matching the JSON format of the legacy txOutToJsonValue. Uses AnyEraTxOut from cardano-ledger to conditionally include datum and reference script fields based on era capabilities, avoiding per-era pattern matching. Standalone instances cover pre-Alonzo eras (Shelley, Allegra, Mary) which only need address and value fields. Helper functions: - addrToJson: renders L.Addr as bech32/base58 - valueToJson: converts to cardano-api Value format - ledgerScriptToScriptInAnyLang: generic script conversion using withPlutusScript, no per-era matching Includes a property test verifying JSON output matches the legacy implementation across all Shelley-based eras.