Cardano Updates

Remove caseByronToAlonzoOrBabbageEraOnwards and simplify value ops

- Remove caseByronToAlonzoOrBabbageEraOnwards from Era.Internal.Case and Era exports
- Replace its usages with caseShelleyToAlonzoOrBabbageEraOnwards (ShelleyBasedEra)
- Simplify adaAssetL and mkAdaValue using Cardano.Ledger.Val (coin, modifyCoin)
- Simplify negateLedgerValue using L.invert, dropping the groups dependency
- Update ReferenceScript JSON instances from IsCardanoEra to IsShelleyBasedEra

Replace the three separate where-bound helpers (datumFields,
inlineDatumFields, refScriptFields) with a single top-level
datumAndRefScriptFields function. Simplifies alonzoOnwardsTxOutToJson
and documents the per-era field layout in one place.

Add per-era FromJSON instances for the experimental TxOut type,
mirroring the ToJSON structure. Pre-Alonzo eras parse address and
value only; Alonzo adds datum hash support; Babbage+ adds inline
datum (parsed from inlineDatumRaw with hash validation) and
reference script support. Supplemental datums are deliberately
unsupported as the ledger TxOut does not carry them.

Replace coercion-based key mapping with Shelley.getOriginalTxIn, removing
the need for the Wno-x-ord-preserving-coercions suppression pragma.

This reverts commit 58320efdc16ce34261fe4202e25304e564639400.