Cardano Updates

T002: Add scripts/check-no-cardano-api.sh
T009-T010: Fix stale CardanoApiEra references in Eras.hs comments
T011: Haddock builds clean, zero cardano-api cross-references
T019: Remove cardano-api from README key dependencies

T002: Add scripts/check-no-cardano-api.sh
T009-T010: Fix stale CardanoApiEra references in Eras.hs comments
T011: Haddock builds clean, zero cardano-api cross-references
T019: Remove cardano-api from README key dependencies

Dijkstra deserializes Conway CBOR identically (backwards compatible).
Reuse the existing 152 Conway golden files for Dijkstra round-trips.

One file (42.cbor) is skipped: it contains a certificate without
deposits, which Conway accepts but Dijkstra rejects
("Certificates without deposits are no longer supported").

151 new Dijkstra serialization tests, 420 total (up from 268).

The cardano-api removal unblocks DijkstraEra at runtime.
34 new tests now run (268 total, up from 234).

4 remaining pending:
- 2x "todo: add test data" (pre-existing)
- 1x Dijkstra serialization golden (needs CBOR files)
- 1x boundedEnumLaws (needs investigation)

Delete orphaned Cardano.Api.Gen module (2056 lines) and remove
cardano-api from test build-depends. Also remove 10 transitive
test deps that were only needed by Gen.hs.

Verified:
- Zero Cardano.Api imports in lib/ and test/
- cardano-api absent from cabal dependency plan
- 234/234 tests pass, 0 assertions modified
- 152 CBOR golden round-trips byte-identical

Remove 10 unused test dependencies left over from Cardano.Api.Gen
deletion. Fix genTxForBalancing to sometimes include collateral
fields so property tests for totalCollateral/returnCollateral
rejection no longer discard all test cases.

Remove 10 unused test dependencies left over from Cardano.Api.Gen
deletion. Fix genTxForBalancing to sometimes include collateral
fields so property tests for totalCollateral/returnCollateral
rejection no longer discard all test cases.

Mark completed: T001, T003-T008, T013
Update T012 scope: Gen.hs is now orphaned, just needs deletion

Rewrite all QuickCheck generators in BalanceSpec.hs to use
cardano-ledger types directly, removing the last cardano-api
usage from the test infrastructure.

Generator population comparison (1000 samples each):

genTxForBalancing @ConwayEra:
                          OLD         NEW
  has inputs:           100.0%      100.0%
  has certificates:      47.5%       44.5%
  has withdrawals:       54.6%       61.0%
  has collateral in:      0.4%        5.0%
  has totalCollat:        4.4%        6.7%
  has returnCollat:       4.8%        3.9%
  has validity lo:      100.0%      100.0%
  has validity hi:       49.1%       49.0%

genTxOut @ConwayEra:
                          OLD         NEW
  shelley:               51.3%       47.4%
  byron:                 48.7%       52.6%
  mainnet:               48.2%       44.8%
  testnet:                3.1%        2.6%
  key pay cred:          24.3%       24.3%
  script pay cred:       27.0%       23.1%
  has stake ref:         25.9%       23.4%

No test assertions were modified. All 234 tests pass.

Remove CardanoApiEra type family, IsShelleyBasedEra constraint,
toCardanoApiTx/fromCardanoApiTx, and all cardano-api imports from
library modules. IsRecentEra now only requires Typeable and
RecentEraConstraints. Enum AnyRecentEra uses manual numbering.

BREAKING CHANGE: CardanoApiEra, toCardanoApiTx, fromCardanoApiTx,
cardanoEraFromRecentEra, shelleyBasedEraFromRecentEra removed from
public API.

Delete Cardano/Api/Gen.hs (~2000 lines of cardano-api generators).
Rewrite BalanceSpec.hs to use ledger-native generators:
- genTxForBalancing: mkBasicTx with random outputs
- genTxOut: mkBasicTxOut with proper Shelley addresses
- genLedgerAddr: Addr Testnet with random KeyHash
- Wallet Arbitrary: ledger TxOut generators
- shrinkTx: simplified to const []
- NetworkId: replaced with local TestNetworkId type
- Remove cardano-api from test build-depends

BREAKING CHANGE: Cardano.Api.Gen test module removed.

Delete Cardano/Api/Gen.hs (~2000 lines of cardano-api generators).
Rewrite BalanceSpec.hs to use ledger-native generators:
- genTxForBalancing: mkBasicTx with random outputs
- genTxOut: mkBasicTxOut with proper Shelley addresses
- genLedgerAddr: Addr Testnet with random KeyHash
- Wallet Arbitrary: ledger TxOut generators
- shrinkTx: simplified to const []
- NetworkId: replaced with local TestNetworkId type
- Remove cardano-api from test build-depends

BREAKING CHANGE: Cardano.Api.Gen test module removed.

Remove CardanoApiEra type family, IsShelleyBasedEra constraint,
toCardanoApiTx/fromCardanoApiTx, and all cardano-api imports from
library modules. IsRecentEra now only requires Typeable and
RecentEraConstraints. Enum AnyRecentEra uses manual numbering.

BREAKING CHANGE: CardanoApiEra, toCardanoApiTx, fromCardanoApiTx,
cardanoEraFromRecentEra, shelleyBasedEraFromRecentEra removed from
public API.

serializeTx now uses Cardano.Ledger.Binary.serialize' directly.
deserializeTx uses decodeFullAnnotator with era-specific decCBOR.
toRecentEraGADT returns Either String instead of AnyCardanoEra.

toCardanoApiTx/fromCardanoApiTx kept for now (test code still
uses them — will be removed with test generator rewrite).

serializeTx now uses Cardano.Ledger.Binary.serialize' directly.
deserializeTx uses decodeFullAnnotator with era-specific decCBOR.
toRecentEraGADT returns Either String instead of AnyCardanoEra.

toCardanoApiTx/fromCardanoApiTx kept for now (test code still
uses them — will be removed with test generator rewrite).

Rewrite estimateKeyWitnessCounts to use ledger lenses and types
directly instead of going through CardanoApi.getTxBodyContent:

- Transaction inputs via inputsTxBodyL + collateralInputsTxBodyL
- Required signers via reqSignerHashesTxBodyG (getter, no AtMostEra)
- Withdrawals via withdrawalsTxBodyL, counting by RewardAccount cred
- Certificates via certsTxBodyL with direct TxCert pattern matching
- Removed txUpdateProposal handling (not in Conway/Dijkstra)
- estimateDelegSigningKeys takes Ledger.TxCert directly

Rewrite estimateKeyWitnessCounts to use ledger lenses and types
directly instead of going through CardanoApi.getTxBodyContent:

- Transaction inputs via inputsTxBodyL + collateralInputsTxBodyL
- Required signers via reqSignerHashesTxBodyG (getter, no AtMostEra)
- Withdrawals via withdrawalsTxBodyL, counting by RewardAccount cred
- Certificates via certsTxBodyL with direct TxCert pattern matching
- Removed txUpdateProposal handling (not in Conway/Dijkstra)
- estimateDelegSigningKeys takes Ledger.TxCert directly

Each of the 153 Conway signedTx golden files now runs as its own
named hspec test, sorted by index. Failures will identify the
exact file rather than just "golden files failed".

Each of the 153 Conway signedTx golden files now runs as its own
named hspec test, sorted by index. Failures will identify the
exact file rather than just "golden files failed".