Cardano Updates

Wait for #2324 to merge.

This makes a couple of changes to the tests:

1. Switch from hspec to tasty. Why? Few reasons, but 1 is I want to try
[tasty-cache](https://github.com/silky/tasty-cache);
2. We get some nice formatted test output in the PRs now:
<img width="870" height="1031" alt="image"
src="https://github.com/user-attachments/assets/0c660f0e-7103-4d78-a2cd-e1b3c2e0f5a6"
/>
3. Some more tests are ran in parallel

OpenDatum.accumulatorHash is only updated by on-chain Increment and
  Decrement transactions. Regular L2 snapshots are off-chain and never
  touch the Open datum, so the field is stale for any head that has
  processed L2 transactions.

  The CRS UTxO is published at an AlwaysFails script address, making it
  unspendable by the ledger rules regardless of the validator body.
  Returning False is therefore not strictly necessary but documents the
  intent: this is a permanently locked datum carrier, not an incomplete
  validator.

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

The plutus-tx-plugin (a GHC plugin) compiles Hydra's Haskell on-chain
scripts to Plutus IR; under GHC 9.12.4 it produces semantically equivalent
but byte-different bytecode than under GHC 9.6.7, leading to different
on-chain script hashes:

  vHead: 4e48afcd87e873c618ae00ee090d52e0451f3d25f1b7d3e397c30b3e
      -> 33c88da88a31e24fa98eeaf94751e9dc5c8d627384df4ba56ba49ab5

  mHead: 5c5cec68dcb9157324fb4030c764890830da6a335410419279a9723e
      -> a804ae87994b0771a78df1fb6c68ff0cc9af71786cc4424307e87f5e

The GoldenSpec module explicitly anticipates this scenario:

> This is also crucial in case we cannot reproduce them exactly as they
> were originally compiled using plutus-tx; which is not unlikely given
> we need to have the exact same version of plutus-tx, all its
> dependencies, and GHC.

Regenerated by deleting the .plutus files and running the golden test
under GHC 9.12.4. Note: anyone publishing scripts from this branch will
deploy them at the new hashes; existing on-chain deployments under the
old hashes remain usable by hydra-nodes pointing at them via
--hydra-scripts-tx-id.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>