cardano-rpc: Populate transaction bodies in FetchBlock responses

[carbolymer]

Context

Part of the node kernel access work (ADR-019): FetchBlock previously returned raw block bytes, the block header and the timestamp, but left body.tx empty.

This PR populates the transaction bodies. All 14 fields of the UTxO RPC Tx message are mapped: inputs, outputs, reference inputs, certificates, withdrawals, mint, witnesses, collateral, fee, validity, successful, auxiliary data, hash and governance proposals.

• Transactions are converted at ledger level for every Shelley-based era; era-gated fields (reference inputs, mint, collateral, proposals) stay empty where the era predates them.
• Spending, withdrawal and certificate redeemers are wired to their entries by script witness index, and successful reflects the phase-2 IsValid flag.
• A new Certificate module maps all 19 certificate variants (Dijkstra-safe via concrete-era dispatch); a new Governance module maps all 7 governance actions including partial parameter updates.
• Byron transactions are converted directly from the Byron ledger types, since cardano-api's Tx era has no Byron constructor. Byron fees are implicit in the UTxO and stay unset; epoch boundary blocks yield no transactions. This makes FetchBlock serve transaction data for the full mainnet history.

The first four commits are small cardano-api prerequisites, each with its own changelog fragment: re-export byronBlockRaw from Cardano.Api.Consensus, add ConwayEraPParams to EraCommonConstraints, export the per-era toScriptIndex variants, and make genTx sign the transaction body it returns.

Known limitations, deliberate and documented in code:

• TxInput.as_output is unset (resolving it requires UTxO lookups).
• Byron fee is unset (implicit in Byron; requires UTxO lookups).
• The Byron positional witness-to-input pairing is not representable in the proto WitnessSet; native_bytes is the fidelity escape hatch.
• Pre-existing bytes-field encoding divergences (TxOutput.address as text, inline Datum.hash carrying CBOR) are tracked separately in gRPC: bytes fields encoded as text or wrong payload (TxOutput.address, Datum.hash) #1246 and not changed here.

How to trust this PR

This PR is integrated and tested end-to-end in IntersectMBO/cardano-node#6579.

The conversion is covered at three levels:

• Property tests (cardano-rpc-test, 77 tests): per-era field projections of generated transactions against the ledger values across all seven Shelley-based eras, certificate arm routing, injected-redeemer wiring (spending/rewarding/certifying at known indices), a wire-level protobuf encode/decode roundtrip forcing total evaluation across all eras, Byron golden tests decoding real block CBOR, and a forged-annotation guard pinning Byron transaction ids to the on-chain bytes rather than a re-serialisation.
• E2E (gRPC: fetchBlock method cardano-node#6579): submits a payment transaction and a native-script minting transaction over gRPC, locates their blocks, fetches them via FetchBlock and asserts the mapped fields (hash, fee, inputs, outputs, validity, mint, witness set contents) against the submitted values, plus the NOT_FOUND and INVALID_ARGUMENT error paths.
• The mapping was cross-checked against other UTxO RPC implementations (Dolos/pallas, Blink Labs/gouroboros) for the byte-encoding conventions of addresses, asset names, hashes and witnesses.

Review commit by commit; every commit builds and passes tests on its own. The conversion lives in Cardano.Rpc.Server.Internal.UtxoRpc.Type.{Tx,Certificate,Governance,Byron} and the handler wiring in Cardano.Rpc.Server.Internal.UtxoRpc.Sync.

Run the tests:

cabal test cardano-rpc-test
TASTY_PATTERN='/RPC FetchBlock/' cabal test cardano-testnet-test

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated. See Running tests for more details
• Self-reviewed the diff
• Changelog fragment added in .changes/

[Copilot]

Pull request overview

This PR extends the cardano-rpc UTxO RPC implementation so FetchBlock returns fully populated transaction bodies (including Byron), backed by new ledger-to-protobuf conversion modules and expanded property/golden test coverage. It also includes supporting cardano-api exports/helpers needed to correctly wire redeemers and access Byron raw blocks.

Changes:

• Populate FetchBlock responses with cardano.body.tx for Shelley-based eras and Byron, using new conversion modules (Type.Tx, Type.Byron, Type.Certificate, Type.Governance).
• Refactor and extend UTxO RPC type mappings (scripts, protocol parameters, tx outputs) and add extensive property/golden tests for mapping correctness across eras.
• Add cardano-api exports for per-era toScriptIndex* helpers and re-export byronBlockRaw for Byron block access.

Reviewed changes

Copilot reviewed 26 out of 28 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
cardano-rpc/test/cardano-rpc-test/Test/Cardano/Rpc/Type.hs	Adds a property test for metadatum integer clamping behavior.
cardano-rpc/test/cardano-rpc-test/Test/Cardano/Rpc/FetchBlockTx.hs	New property tests projecting txToUtxoRpcTx results against ledger facts across eras.
cardano-rpc/test/cardano-rpc-test/Test/Cardano/Rpc/ByronTx.hs	New property/golden tests for Byron tx/block conversion.
cardano-rpc/src/Cardano/Rpc/Server/Internal/UtxoRpc/Type/TxOutput.hs	Extracts reusable multiasset conversion helper.
cardano-rpc/src/Cardano/Rpc/Server/Internal/UtxoRpc/Type/Tx.hs	New Shelley-based ledger-tx → UTxO RPC Tx conversion including redeemer wiring.
cardano-rpc/src/Cardano/Rpc/Server/Internal/UtxoRpc/Type/Script.hs	Factors out scriptToUtxoRpcScript for reuse.
cardano-rpc/src/Cardano/Rpc/Server/Internal/UtxoRpc/Type/ProtocolParameters.hs	Reworks protocol parameter mapping using HKD setters; adds protocol version conversion helper.
cardano-rpc/src/Cardano/Rpc/Server/Internal/UtxoRpc/Type/Governance.hs	New mapping for Conway governance proposals/actions to proto.
cardano-rpc/src/Cardano/Rpc/Server/Internal/UtxoRpc/Type/Certificate.hs	New mapping for Shelley/Conway/Dijkstra certificate variants to proto.
cardano-rpc/src/Cardano/Rpc/Server/Internal/UtxoRpc/Type/Byron.hs	New conversion for Byron-era txs and block tx extraction.
cardano-rpc/src/Cardano/Rpc/Server/Internal/UtxoRpc/Type.hs	Re-exports newly introduced conversion entry points.
cardano-rpc/src/Cardano/Rpc/Server/Internal/UtxoRpc/Sync.hs	Wires FetchBlock to include populated transaction bodies.
cardano-rpc/src/Cardano/Rpc/Server/Internal/Orphans.hs	Adds Inject instance for protocol version mapping.
cardano-rpc/README.md	Updates feature matrix to mark FetchBlock as supported.
cardano-rpc/cardano-rpc.cabal	Registers new modules and dependencies; wires new test modules.
cardano-api/src/Cardano/Api/Tx/Internal/Body.hs	Exports toScriptIndexAlonzo/Conway/Dijkstra and generalises their types.
cardano-api/src/Cardano/Api/Tx.hs	Re-exports the per-era toScriptIndex* helpers from the public API.
cardano-api/src/Cardano/Api/Experimental/Era.hs	Adds ConwayEraPParams to EraCommonConstraints (changelog marked breaking).
cardano-api/src/Cardano/Api/Consensus/Internal/Reexport.hs	Re-exports consensus byronBlockRaw.
cardano-api/src/Cardano/Api/Consensus.hs	Exposes byronBlockRaw from the public consensus API.
cardano-api/gen/Test/Gen/Cardano/Api/Typed.hs	Adjusts genTx to sign a single body; adds genTxWitnesses.
.changes/20260715_cardano_api_gen_tx_single_body.yml	Changelog fragment for generator/testlib adjustment.
.changes/20260715_cardano_api_export_to_script_index_variants.yml	Changelog fragment for new toScriptIndex* exports.
.changes/20260715_cardano_api_conway_pparams_common_constraints.yml	Changelog fragment marking added constraint as breaking.
.changes/20260708_cardano_rpc_fetchblock_tx_bodies.yml	Changelog fragment for FetchBlock tx body population feature.
.changes/20260708_cardano_api_byron_block_raw_reexport.yml	Changelog fragment for byronBlockRaw re-export.

[carbolymer]

Tracking this in: #1246