cardano-rpc: Add ReadGenesis method

[carbolymer]

Context

Implements the UTxO RPC QueryService.ReadGenesis method in cardano-rpc.
Fixes #1217.

The response carries:

• genesis - the Blake2b-256 hash of the raw Shelley genesis file bytes, matching what Dolos returns and what cardano-node itself computes at startup.
• caip2 - a chain identifier keyed on the Shelley network magic: cardano:mainnet, cardano:preprod, cardano:preview, or cardano:<magic> for other networks (matches Dolos, since the spec leaves the format open).
• cardano - the full per-era genesis configuration: Byron (proto fields 1-9), Shelley (10-23, including initial_funds), Alonzo (24-31) and Conway (32-42), with cost_models composed from Alonzo's PlutusV1 and Conway's PlutusV3 models.

The handler performs no disk reads: all genesis data comes from values cardano-node already parsed at boot, threaded into mkNodeKernelAccess via ProtocolInfoArgs (whose TransitionConfig retains the full, uncompacted ShelleyGenesis - consensus's own copy erases sgInitialFunds/sgStaking) and a Shelley genesis hash returned alongside SomeConsensusProtocol. The cardano-node side of that threading is a separate cardano-node PR.

How to trust this PR

• The commit sequence separates the proto change, the regenerated code, the cardano-api export additions, the implementation and the tests - the Regenerate proto code commit can be skipped when reviewing.
• Test.Cardano.Rpc.Genesis.Fixture proves the wire encodings byte-for-byte against trimmed mainnet genesis JSON parsed with the ledger's own readers (AVVM base64 keys, base58 Byron addresses, hex hashes, LovelacePortion numerators, the seconds-to-milliseconds slotLength conversion).
• Test.Cardano.Rpc.Genesis.Property checks structural correspondence of all four era mappers on arbitrary ledger-generated genesis values (map sizes, key sets, exact rational numerators/denominators).
• An end-to-end test (TASTY_PATTERN='/RPC ReadGenesis/' cabal test cardano-testnet-test, in the cardano-node PR) starts a testnet with RPC enabled and asserts initial_funds is non-empty - which only holds if the uncompacted boot-time genesis reaches the wire.
• Run the whole unit suite with TASTY_PATTERN='genesis' cabal test cardano-rpc-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

Implements the UTxO RPC QueryService.ReadGenesis endpoint in cardano-rpc, sourcing per-era genesis configuration from in-process node kernel access (boot-time parsed configs) and exposing it over gRPC along with a Shelley genesis hash and CAIP-2 chain identifier.

Changes:

• Add ReadGenesis to the QueryService proto and generated bindings, wire it into the server, and implement readGenesisMethod.
• Introduce a GenesisBundle in node-kernel access and a new UtxoRpc.Type.Genesis mapper to populate the full per-era cardano.Genesis message (Byron/Shelley/Alonzo/Conway).
• Add fixture-based and property-based tests plus genesis JSON fixtures to validate mapping/encoding.

Reviewed changes

Copilot reviewed 25 out of 25 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
cardano-rpc/src/Cardano/Rpc/Server/Internal/UtxoRpc/Query.hs	Implements readGenesisMethod, CAIP-2 derivation, and returns genesis hash + mapped config.
cardano-rpc/src/Cardano/Rpc/Server/Internal/UtxoRpc/Type/Genesis.hs	New conversion module mapping per-era ledger genesis/params into the U5c.Genesis proto.
cardano-rpc/src/Cardano/Rpc/Server/NodeKernelAccess/Type.hs	Adds GenesisBundle and stores genesis config in NodeKernelAccess.
cardano-rpc/src/Cardano/Rpc/Server/NodeKernelAccess.hs	Changes mkNodeKernelAccess to accept boot-time inputs and builds GenesisBundle.
cardano-rpc/src/Cardano/Rpc/Server/Internal/Tracing.hs	Adds new trace constructors for ReadGenesis and node-kernel-access events.
cardano-rpc/src/Cardano/Rpc/Server.hs	Registers ReadGenesis handler and wraps it in a tracing span.
cardano-rpc/proto/utxorpc/v1beta/query/query.proto	Adds rpc ReadGenesis(...) to QueryService.
cardano-rpc/gen/Proto/Utxorpc/V1beta/Query/Query.hs	Regenerated service bindings to include ReadGenesis.
cardano-rpc/src/Cardano/Rpc/Server/Internal/UtxoRpc/Type/Certificate.hs	Factors constitution conversion into a shared helper (reused by genesis mapping).
cardano-rpc/src/Cardano/Rpc/Server/Internal/UtxoRpc/Type/Governance.hs	Uses the new constitution helper.
cardano-rpc/src/Cardano/Rpc/Server/Internal/UtxoRpc/Type.hs	Re-exports genesisBundleToProto.
cardano-rpc/cardano-rpc.cabal	Adds new module and dependencies; extends test-suite deps and modules.
cardano-rpc/test/cardano-rpc-test/Test/Cardano/Rpc/Genesis/Fixture.hs	Differential tests against real (trimmed) mainnet genesis JSON fixtures.
cardano-rpc/test/cardano-rpc-test/Test/Cardano/Rpc/Genesis/Property.hs	Structural property tests for all era mappers with bounded generators/clipping.
cardano-rpc/test/cardano-rpc-test/files/genesis/byron-genesis.json	Byron genesis fixture.
cardano-rpc/test/cardano-rpc-test/files/genesis/shelley-genesis.json	Shelley genesis fixture.
cardano-rpc/test/cardano-rpc-test/files/genesis/alonzo-genesis.json	Alonzo genesis fixture.
cardano-rpc/test/cardano-rpc-test/files/genesis/conway-genesis.json	Conway genesis fixture.
cardano-rpc/test/cardano-rpc-test/cardano-rpc-test.hs	Adjusts tasty-discover options.
cardano-api/src/Cardano/Api/LedgerState.hs	Exports readShelleyGenesis + error types for downstream use.
cardano-api/src/Cardano/Api/Consensus.hs	Re-exports additional consensus helpers needed for node-kernel threading.
cardano-api/src/Cardano/Api/Consensus/Internal/Protocol.hs	Exposes helpers to extract transition config / Byron params from protocol args.
cardano-api/src/Cardano/Api/Consensus/Internal/Reexport.hs	Re-exports shelleyLedgerGenesis.
.changes/20260804_cardano_rpc_readgenesis.yml	Changelog fragment for cardano-rpc ReadGenesis work.
.changes/20260804_cardano_api_readgenesis_reexports.yml	Changelog fragment for cardano-api export/re-export additions.