Cardano Updates

Co-authored-by: Alexey Kuleshevich <[email protected]>

Extends the ChainDB model with generator state to support carrying gap
blocks in state machine tests. This increases the chances of generating
and adding (possibly out-of-order) branching sequences of blocks. This,
in turn increases the chances of observing the event where the
chain selection logic switches from a longer to a shorter (but heavier)
chain containing a boosted block.

This commit increases the generation frequencies of both the
'genAddBlock' and 'genAddPerasCert' constructions to help producing
denser chains of blocks. This way, some of the events that were
harder to trigger (especially TagSwitchedToShorterChain) are much
more common now:

* Before:
    Tags (5784 in total):
    39.83% TagGetIsValidJust
    29.72% TagChainSelReprocessKeptSelection
    27.92% TagGetIsValidNothing
     2.42% TagChainSelReprocessChangedSelection
     0.10% TagSwitchedToShorterChain

* After:
    Tags (5202 in total):
    38.66% TagGetIsValidJust
    27.87% TagChainSelReprocessKeptSelection
    26.43% TagGetIsValidNothing
     5.71% TagChainSelReprocessChangedSelection
     1.33% TagSwitchedToShorterChain

Since the Peras boost per certificate will likely become a protocol
parameter, we proactively avoid exposing the current hardcoded value,
replacing it with an instantiation of (currently trivial) the PerasCfg
builder.

In the special cases where it's interesting to vary the boost
dynamically (ChainDB q-s-m), validated Peras certs now contain randomly
generated boost weights.

After analysing the effect of varying the security parameter (`k`) of
the ChainDB state machine tests (currently hardcoded with 2), we have
observed a tension between:

1) generating enough tests exercising the new Peras behavior where the
   chain selection mechanism switches to a shorter but heavier chain
   (cert boost is derived from k and must be large enough to overcome
   the weight of a longer chain), and

2) generating enough tests exercising the ImmutableDB logic (the chain
   must have at least k blocks)

Here are some empirical results:

k   -> P(switch to shorter chain), P(generate a chain with >= k blocks)
k=2 -> ~1.3%, ~40%
k=3 -> ~1.9%, ~20%
k=4 -> ~2.4%, ~9%
k=5 -> ~2.5%, ~3%
k=10 -> ~3%,  ~0.05%

We believe that the sweet spot between both desiderata appears to be
around `k=2` and `k=4`.

This commit introduces a random generator for `k` using a geometric
distribution to bias the randomly generated `k`s to be relatively small,
while still allowing larger ones to appear from time to time.

Under the current parameters, roughly 87.5% of the tests use `k<=4`;

```
Security Parameter (k) (10000 in total):
  50.82% 2
  23.83% 3
  12.62% 4
   6.69% 5
   3.08% 6
   1.54% 7
   0.74% 8
   0.37% 9
   0.16% 10
   0.06% 11
   0.05% 12
   0.02% 13
   0.01% 14
   0.01% 17
```

Yielding the following distributions for 1) and 2), respectively:

```
Tags (5161 in total):
  39.35% TagGetIsValidJust
  29.22% TagChainSelReprocessKeptSelection
  25.91% TagGetIsValidNothing
   3.88% TagChainSelReprocessChangedSelection
   1.65% TagSwitchedToShorterChain  <- HERE
```

```
Chain length >= k (10000 in total):
  73.25% False
  26.75% True  <- HERE
```

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Bumps [golangci/golangci-lint-action](https://github.com/golangci/golangci-lint-action) from 9.0.0 to 9.1.0.
- [Release notes](https://github.com/golangci/golangci-lint-action/releases)
- [Commits](https://github.com/golangci/golangci-lint-action/compare/0a35821d5c230e903fcfe077583637dea1b27b47...e7fa5ac41e1cf5b7d48e45e42232ce7ada589601)

---
updated-dependencies:
- dependency-name: golangci/golangci-lint-action
  dependency-version: 9.1.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Bumps [actions/checkout](https://github.com/actions/checkout) from 5.0.0 to 6.0.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Commits](https://github.com/actions/checkout/compare/v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: 6.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Bumps [actions/setup-go](https://github.com/actions/setup-go) from 6.0.0 to 6.1.0.
- [Release notes](https://github.com/actions/setup-go/releases)
- [Commits](https://github.com/actions/setup-go/compare/44694675825211faa026b3c33043df3e48a5fa00...4dc6199c7b1a012772edbd06daecab0f50c9053c)

---
updated-dependencies:
- dependency-name: actions/setup-go
  dependency-version: 6.1.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

See https://github.com/IntersectMBO/plutus/issues/7415#issuecomment-3531989244
See https://gitlab.haskell.org/ghc/ghc/-/merge_requests/15096

Bumps [github.com/blinklabs-io/gouroboros](https://github.com/blinklabs-io/gouroboros) from 0.139.0 to 0.140.0.
- [Release notes](https://github.com/blinklabs-io/gouroboros/releases)
- [Commits](https://github.com/blinklabs-io/gouroboros/compare/v0.139.0...v0.140.0)

---
updated-dependencies:
- dependency-name: github.com/blinklabs-io/gouroboros
  dependency-version: 0.140.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Bumps [github.com/blinklabs-io/cardano-models](https://github.com/blinklabs-io/cardano-models) from 0.6.0 to 0.7.0.
- [Release notes](https://github.com/blinklabs-io/cardano-models/releases)
- [Commits](https://github.com/blinklabs-io/cardano-models/compare/v0.6.0...v0.7.0)

---
updated-dependencies:
- dependency-name: github.com/blinklabs-io/cardano-models
  dependency-version: 0.7.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Bumps [actions/checkout](https://github.com/actions/checkout) from 5.0.1 to 6.0.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Commits](https://github.com/actions/checkout/compare/v5.0.1...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: 6.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

The feature is self-explanatory and doesn't require additional documentation file.