Cardano Updates

Remove the "genesis spec" workbench command that was used for `create-testnet-data --spec-*` and instead use what cardano-profile provides.

The profile may have null "conway" or "dijkstra" genesis fields but the node still needs valid files, use a "zero" genesis in those cases.

Based on a mainnet db-sync and mainnet genesis files we reconstructed the timeline with no cardano-profile implementation specifics

Going forward, the only way to inject cost models with any number of parameters is through Alonzo genesis "extraConfig" field.

- Structure: Separates cost models from the rest of the parameters.
- Consistency: Shelley genesis is the full object, no only the "protocolParams" field.
- Consistency: Uses everywhere an object for the cost model, no arrays.
- Cost model names are updated.

Were removed when the node started only considering valid what mainnet shipped with

Two sites in amaru-ledger/src/state.rs were doing unchecked Epoch
subtraction on a u64-backed Epoch, producing u64::MAX-1 (or panicking,
depending on overflow checks) when the latest snapshot or the
slot-derived current epoch was below the rewards/leader-schedule
horizon (epoch < 2):

- StakeDistributionObserver::get_pool: `current_epoch - 2` becomes
  saturating_sub(2). Headers validated very early in the chain (or
  with a custom era history that maps slots to low epoch numbers)
  no longer surface a misleading
  "no stake distribution available for pool access 18446744073709551614"
  — the error now correctly says "pool access 0" and points at a
  real missing snapshot.

- initial_stake_distributions: `latest_epoch - Epoch::from(2)` and
  `- Epoch::from(1)` become saturating_sub(2) / saturating_sub(1).
  Bundles produced by amaru-bootstrap from cold-start short-epoch
  testnets (e.g. lambdasistemi/amaru-bootstrap#34's antithesis
  reproducer) where the most_recent_snapshot is epoch 0 or 1 no
  longer hit a u64 underflow on Ledger::new; for_epoch(0) is
  exercised normally and surfaces a sensible StoreError if the
  snapshot is genuinely absent.

This is a defensive correctness improvement only — it does not change
behaviour for any chain past epoch 2. Surfaced by the new live
amaru-run consumer test in lambdasistemi/amaru-bootstrap#35.

Signed-off-by: Paolo Veronelli <[email protected]>
Signed-off-by: paolino <[email protected]>

Signed-off-by: paolino <[email protected]>

The node-snapshot (tvar) import path derived the current era's epoch size
from the network default (86400), ignoring custom-testnet genesis. Load the
history.<slot>.<hash>.json sidecar (as the .cbor path already does via
make_era_history) and use it to interpret the snapshot, but only for
Testnet(_); public networks keep the snapshot-derived history unchanged.

Signed-off-by: paolino <[email protected]>

assert_leader_stake currently computes c = ln(1 - active_slot_coeff)
unconditionally. For genesis params with activeSlotsCoeff = 1.0
(used by the antithesis short-epoch fixture in
lambdasistemi/amaru-bootstrap and by the live consumer test in
lambdasistemi/amaru-bootstrap#35) this is ln(0), and pallas-math's
FixedDecimal::ln panics with "ln of a value in (-inf,0] is undefined".

When f = 1, every slot is leader-elected with probability 1 — the
leader-stake assertion is trivially satisfied for any pool with
non-zero relative stake. Mirroring the pre-existing zero-active-stake
guard added in b69fa13e, short-circuit to Ok before the ln call.

The math is continuous at f -> 1 (exp(x*c) with c -> -inf collapses
to 0, which is < recip_q, so the ordering is LT = Ok), so the guard
does not change behaviour for any f < 1.

Surfaced by the live amaru-run consumer test in
lambdasistemi/amaru-bootstrap#35 once
lambdasistemi/amaru#2 (saturating epoch subtraction) let header
validation reach this code path on a cold-start short-epoch chain.

Signed-off-by: Paolo Veronelli <[email protected]>
Signed-off-by: paolino <[email protected]>

Signed-off-by: paolino <[email protected]>

Port of lambdasistemi 36ea009c onto upstream/main's rewritten state.rs.

Generated private testnets (db-synthesizer / amaru-bootstrap) can serve
block headers from the next leader schedule before the stable ledger
has materialized that epoch's snapshot. Add an opt-in forecast on
StakeDistributionObserver::get_pool that falls back to the latest
cached distribution when the requested epoch is strictly newer; only
enabled for NetworkName::Testnet(_).

Public networks (mainnet/preprod/preview) keep the existing strict
lookup behaviour.

Signed-off-by: paolino <[email protected]>

Signed-off-by: paolino <[email protected]>