Cardano Updates

Replace these partials with more type-safe (Shelley)EraForecast, clearly
separating TPraos forecasts from Praos ones, and also distinguising
current and future forecasts in their respective types.

Also change PredicateFailure TICKN to be Void, and remove empty datatype
TicknPredicateFailure.

Update ConwayTICKF to have Void as its PredicateFailure. This makes the
implementation clearer while also allowing futureForecast to be pure.

Forecast t BabbageEra = BabbageForecast t BabbageEra

This is the first set of changes to deprecate GetLedgerView et. al. from
cardano-ledger-tpraos.[^1]

This makes everything more type-safe, clearly separating TPraos forecasts
from those for Praos. It also distinguishes current from future forecasts
at the type-level.

[^1]: https://github.com/IntersectMBO/cardano-ledger/issues/5617

Added the following tests:

* JSON roundtrip property test
* Unit test for trying to decode an empty object `{}` for the
  `NonEmptyMap`, and an empty list `[]` for the `NonEmptySet`. These
  scenarios are expected to fail with a specific error message.

Add withGenerator to plutus_v4_script to prevent set collisions, matching
the fix for V1/V2/V3. Enable previously disabled Dijkstra tests that now
pass: AuxData roundtrip, TxOut/Script/TxWits ArbitraryValidate,
PParamsUpdate/ProposalProcedure/GovAction ArbitraryValidate, and TxAuxData
decoder equivalence. Update xdescribe reasons for tests that remain
disabled (plutus_v4_script tag 4 not yet supported by decoder, metadatum
validation, empty redeemers).

Co-Authored-By: Claude Opus 4.6 <[email protected]>

Added the following tests:

* JSON roundtrip property test
* Unit test for trying to decode an empty object `{}` for the
  `NonEmptyMap`, and an empty list `[]` for the `NonEmptySet`. These
  scenarios are expected to fail with a specific error message.

* Export reusable validations to future eras and update the BBODY signal.
* Move isOverlaySlot calculation into incrBlock.