Cardano Updates

Re-authored on top of c175b1b317 (the cardano-ledger commit compatible
with consensus main's CHaP index-state 2026-04-13) to match the older
fat-constructor DijkstraBlockBody shape (pre-memoization refactor).
Equivalent to b6b2feb006 on leios-prototype-remake, which targeted the
post-memoization shape (DijkstraBlockBodyRaw + lensMemoRawType).

Adds:
* `dbbLeiosCert :: StrictMaybe LeiosCert` field and matching
  `dbbLeiosCertBytes :: Maybe BSL.ByteString` byte-cache, mirroring the
  PerasCert pattern in this older shape.
* `LeiosCert` placeholder newtype over ByteString with derived
  EncCBOR/DecCBOR/NoThunks/NFData (the real type lands with the Leios
  voting machinery).
* `leiosCertBlockBodyL` lens method on `DijkstraEraBlockBody`.
* Pattern synonym extended with a third `StrictMaybe LeiosCert` arg;
  body threads the bytes through `hashDijkstraSegWits` (now takes the
  Leios bytes arg too).
* `EncCBORGroup` appends the optional Leios cert bytes after the
  optional Peras cert bytes.
* `DecCBOR` handles three list-length cases: 4 (neither), 5 (Peras
  only, legacy), 6 (Peras + Leios). A Leios-only encoding is not
  expressible without ambiguity at len 5 \-- intentional: Dijkstra-era
  blocks aren't on the wire yet.
* `NoThunks` `AllowThunksIn` list extended with `dbbLeiosCertBytes`.
* Testlib: `Arbitrary LeiosCert` (and `DijkstraBlockBody <*> arbitrary
  <*> arbitrary <*> arbitrary`); `ToExpr LeiosCert` and updated
  `ToExpr (DijkstraBlockBody era)` constraint set.

Only the Dijkstra era is Leios-enabled \-- earlier eras are untouched.

Verified: `cabal build cardano-ledger-dijkstra:lib:cardano-ledger-dijkstra`
and `cabal build cardano-ledger-dijkstra:lib:testlib` both clean.

Co-Authored-By: Claude Opus 4.7 <[email protected]>

* `epochInfoRange`
* `startStep`
* `pulseStep`
* `completeStep`
* `lift`

This will use the correct package database

It doesn't work reliably and is incompatible with a nix environment

This brings in https://github.com/input-output-hk/haskell.nix/pull/2498
which is needed for doctesting in nix