Cardano Updates

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 CDDL spec requires `bytes .size (0..64)` and `text .size (0..64)`
for transaction metadatum, but the decoder did not enforce these limits.
This moves the size validation into `decodeMetadatum` so it aligns with
the CDDL spec. The `Arbitrary Metadatum` instance is also constrained
to produce valid values, and the previously disabled CDDL anti-tests
are now enabled.

Changes made with the help of an LLM

Forecast t BabbageEra = BabbageForecast t BabbageEra

Migrate scripts to `cardano-ledger-release-tool`

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

Enable Shelley anti-tests for update, proposed_protocol_parameter_updates,
protocol_param_update, and certificate. Enable Dijkstra transaction
arbitrary validate test that previously hung. Remaining xdescribes are
for unrelated issues.

Changes made with the help of an LLM

* Add ./script/nixpkgs-fmt.sh for non-Nix users.
* Add nixpkgs-fmt in our Nix pre-commit hook.
* Add Github CI check

Optimize Text byte length check in metadata and other places

Refactor such that each example from an era is build on top of the
example of the previous era.

Allows:
* reduced duplication
* each example of each era has most fields set with values

Refactor such that each example from an era is build on top of the
example of the previous era.

Allows:
* reduced duplication
* each example of each era has most fields set with values

since it should be moved to top level UTXOW

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

`validateInputSetEmptyUTxO`, `validateBadInputsUTxO`,
`validateMaxTxSizeUTxO`, `validateOutputBootAddrAttrsTooBig``

See: #5477

Export reusable validations to future eras and update the BBODY signal.

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