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.

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

* Add ./script/nix-format.sh for non-Nix users.
* Add nixfmt in our Nix pre-commit hook.
* Add Github CI check

Bumps [requests](https://github.com/psf/requests) from 2.32.4 to 2.33.0.
- [Release notes](https://github.com/psf/requests/releases)
- [Changelog](https://github.com/psf/requests/blob/main/HISTORY.md)
- [Commits](https://github.com/psf/requests/compare/v2.32.4...v2.33.0)

---
updated-dependencies:
- dependency-name: requests
  dependency-version: 2.33.0
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

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

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

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.

* Add ./script/nix-format.sh for non-Nix users.
* Add nixfmt in our Nix pre-commit hook.
* Add Github CI check

The metadatum decoder now only enforces bytes/text size limits (0..64)
for decoder versions > 2, matching the previous SoftForks.validMetadata
behavior. Tests are added to roundTripShelleyCommonSpec so they run for
every era: accepting oversized values at version 2 (Shelley) and
rejecting them from version 3 (Allegra) onwards.

Changes made with the help of an LLM

The decoder now enforces bytes/text size limits (0..64) for metadatums,
making the rule-level validMetadatum check redundant. Remove
validMetadatum, the SoftForks.validMetadata gate, and the Allegra
InvalidMetadata imp test that relied on constructing invalid metadatums
in-memory.

Changes made with the help of an LLM

Test that bytes/text up to 64 bytes decode successfully, and that
values exceeding 64 bytes are rejected.

Changes made with the help of an LLM