Cardano Updates

since it should be moved to top level UTXOW

TxSubmission protocol was implemented but only wired on the server side.
Client connections never negotiated it, so outbound peers couldn't push
transactions. Register in client_protocol_configs, add spawn_txsubmission,
wire into peer_task/duplex_task/coordinator with broadcast semantics.

Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>

Signed-off-by: Sasha Bogicevic <[email protected]>

Signed-off-by: Eric Torreborre <[email protected]>

Signed-off-by: Eric Torreborre <[email protected]>

- v2 had a different nested structure
- prevents breakage on new installs as well as existing

- v2 had a different nested structure
- prevents breakage on new installs as well as existing

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

CIP-0164 specifies that a server should disconnect if the client
requests an EB or its transactions that the server does not have.
Replace unwrap_or_default() with explicit Option matching — None
now breaks the server loop, triggering disconnect.

Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>

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

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