cardano-rpc: replace remaining old cardano-api usage with ledger-direct conversions

PR #1247's review established the direction: cardano-rpc reads chain data, so its conversions should consume ledger types directly instead of detouring through the old cardano-api.
That PR migrated script witnesses, auxiliary scripts (`ledgerScriptToUtxoRpcScript`) and redeemer classification (`toPlutusScriptPurposeIndex`) to this pattern.
This issue tracks replacing the rest.
The inventory below is initial and will be extended as more usage is found.

## Remaining old-API usage

**`Type/TxOutput.hs` - the largest cluster, old-API end to end.**
All seven exported functions take or return old-API `TxOut CtxUTxO era`, `UTxO era`, `Value`/`PolicyAssets`, in both directions.
The encode side is fed from the ledger anyway: `txToUtxoRpcTx` converts `body ^. L.outputsTxBodyL` through `fromShelleyTxOut` purely to satisfy the old-API input type, losing direct access to the ledger reference script (`referenceScriptTxOutL`) in the process.
The decode side (`utxoRpcTxOutputToTxOut` -> `anyUtxoDataUtxoRpcToUtxo`) is a clean, independently migratable chain.
Migrating this module is also the natural place to fix the wire-format bugs in #1246 (address serialised as UTF-8 text instead of raw bytes, inline datum hash populated with datum CBOR), since those live in exactly the conversions a migration rewrites.

**`Type/Script.hs` - legacy encode and decode helpers.**
`scriptToUtxoRpcScript` and `simpleScriptToUtxoRpcNativeScript` (encode) survive only for `referenceScriptToUtxoRpcScript`, i.e. the TxOutput pipeline above; they can be deleted once TxOutput's encode side migrates.
`utxoRpcNativeScriptToSimpleScript` and `utxoRpcScriptToReferenceScript` (decode) produce old-API `SimpleScript`/`ReferenceScript` and follow the TxOutput decode migration.

**`Type/TxEval.hs` - blocked on cardano-api.**
The evalTx path runs on the old API by necessity: `evaluateTransactionExecutionUnits` returns `Map ScriptWitnessIndex ...` and `ScriptExecutionError` carries `ScriptWitnessIndex`; a bridge (`scriptWitnessIndexToPlutusScriptPurpose`) converts at the seam.
This part cannot migrate until cardano-api's evaluation/fee machinery moves off `ScriptWitnessIndex` (the experimental fee path currently reuses it internally).

**`Type/Tx.hs` and `Type/Certificate.hs` - residual conversion helpers.**
Individual old-API conversions remain in otherwise ledger-direct code: `fromShelleyTxIn`, `fromShelleyStakeAddr`, `fromShelleyTxId`, `fromAlonzoData`/`getScriptData` (datums), `fromAlonzoExUnits`.
These are small and mostly serialisation-only; each needs a case-by-case check whether a ledger-direct equivalent is available.

## Migration approach

Follow the pattern established in #1247: a `ShelleyBasedEra era` witness, concrete-era dispatch (compile-error tripwire for new eras), ledger lenses and classes, byte-identical wire output verified by old-vs-new equivalence properties.
Note that the experimental API's construction-side types are NOT the replacement for reading paths: `AnyScript`'s plutus representation forces script deserialisation (`decodePlutusRunnable`), turning total conversions partial - reading code should consume ledger types directly.

Suggested order:
1. TxOutput encode side (ledger `TxOut` in, includes reference scripts; delete the legacy Script.hs encoders after).
2. #1246 wire-format fixes, in the same series.
3. TxOutput decode side and the Script.hs decode helpers.
4. TxEval, once the cardano-api prerequisite lands.

## Related

- #1246 - wire-format issues, absorbed by step 2.
- #1263 - Dijkstra era gaps (guard scripts convert gracefully since #1247, but the spec cannot represent them).
- #1247 - the PR that established the pattern and migrated the first conversions.

Start with Type/TxOutput.hs and the ledger-direct migration pattern from PR #1247, focusing first on the encode side. Trace the TxOut and reference-script conversions, then review the old-vs-new equivalence properties and the related #1246 wire-format fixes. Done means the remaining conversions follow the stated migration order without unnecessary old cardano-api types.

Written by the indexing model from the issue text.