gRPC: add evalTx

[carbolymer]

Context

This PR adds an implementation of evalTx query.

Upstreamed changes to proto files:

• feat(cardano): Add redeemer index to EvalTx traces and errors utxorpc/spec#202

Test in cardano-testnet:

• gRPC: Add evalTx test cardano-node#6557

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

Adds an EvalTx gRPC endpoint to cardano-rpc’s UTxO RPC SubmitService, enabling evaluation of a CBOR-serialised transaction against the current ledger state (without submission) and returning fee, execution units, traces, and per-redeemer errors.

Changes:

• Extend SubmitService protobuf service with EvalTx and regenerate the Submit service bindings.
• Implement eval handler + supporting conversion utilities for redeemers, errors, traces, and PlutusData roundtrips.
• Add Hedgehog/Tasty-Discover tests covering new conversion and assembly logic; update docs to reflect spec coverage.

Reviewed changes

Copilot reviewed 18 out of 18 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
PLAN-evaltx.md	Implementation plan / design notes for EvalTx.
cardano-rpc/test/cardano-rpc-test/Test/Cardano/Rpc/Type.hs	Adds PlutusData roundtrip property using new inverse conversion.
cardano-rpc/test/cardano-rpc-test/Test/Cardano/Rpc/Eval.hs	New test module for redeemer purpose mapping, redeemer assembly, TxEval assembly, and error reporting.
cardano-rpc/src/Cardano/Rpc/Server/Internal/UtxoRpc/Type.hs	Adds PlutusData inverse conversion and helpers to build EvalTx proto structures.
cardano-rpc/src/Cardano/Rpc/Server/Internal/UtxoRpc/Eval.hs	New evalTxMethod implementation: decode tx, query node, evaluate, compute fee, assemble response.
cardano-rpc/src/Cardano/Rpc/Server/Internal/Tracing.hs	Adds tracing constructors for eval span + decoding failures.
cardano-rpc/src/Cardano/Rpc/Server/Internal/Orphans.hs	Minor cleanup (removes stray comment).
cardano-rpc/src/Cardano/Rpc/Server.hs	Registers EvalTx in the SubmitService method table and improves top-level comments.
cardano-rpc/src/Cardano/Rpc/Proto/Api/UtxoRpc/Submit.hs	Adjusts hidden field imports to expose cardano lenses needed by new response assembly.
cardano-rpc/README.md	Documents UTxO RPC v1beta method coverage and updates build prerequisites text.
cardano-rpc/proto/utxorpc/v1beta/submit/submit.proto	Adds EvalTx RPC method to SubmitService.
cardano-rpc/proto/utxorpc/v1beta/cardano/cardano.proto	Reworks evaluation reporting schema (EvalReport, updated TxEval fields).
cardano-rpc/gen/Proto/Utxorpc/V1beta/Submit/Submit.hs	Regenerated service bindings to include EvalTx.
cardano-rpc/gen/Proto/Utxorpc/V1beta/Cardano/Cardano.hs	Regenerated code reflecting evaluation schema changes.
cardano-rpc/cardano-rpc.cabal	Exposes new eval module; adds new test module and required deps.
cardano-api/src/Cardano/Api/Experimental.hs	Exports evaluateTransactionExecutionUnits from Cardano.Api.Experimental.
.changes/20260508_cardano_rpc_evaltx.yml	Changelog fragment for cardano-rpc EvalTx addition.
.changes/20260508_cardano_api_export_evaluateTransactionExecutionUnits.yml	Changelog fragment for cardano-api experimental export.

[Jimbo4350]

evalTxMethod does not check that the tx is balanced. Is this intentional?

[Copilot]

Pull request overview

Copilot reviewed 19 out of 19 changed files in this pull request and generated 2 comments.

[Jimbo4350]

LGTM. You should extract the logic of evalTxMethod as it differs from our tx balancing functionality in that we don't add a change output. It would be a useful addition I think to cardano-api.