Cardano Updates

to fix the tests failing because of the new predicate failure

for bug report see https://github.com/agda/agda/issues/8532

For consistency with SUBUTXOW

Extend scripts/smoke-test.sh past the cardano-cli ping +
sidecar-convergence checks to drive the tx-generator
daemon through its core contract:

* Wait for the control socket to bind under
  /state/tx-generator-control.sock.
* Probe `{"ready":null}` until the indexer + faucet
  detection both flip true.
* Drive one parallel_driver_refill via docker exec.
* Poll `{"snapshot":null}` until the indexer observes the
  refill (populationSize > 0).
* Drive 5 parallel_driver_transact bursts; tolerate
  no-pickable-source / index-not-ready exits as the
  composer does.
* Final snapshot must show populationSize >= 2 and at
  least one transact landed.

The same scripts are what the Antithesis composer drives
at much heavier load on the cluster; this gives us a CI
gate that catches breakage before the Antithesis-side run.

Triggered via .github/workflows/smoke-test.yaml after
publish-images succeeds.

Replace the local-build :9f91d6f-dirty placeholder with the
real commit SHA cd750e8. publish-images.yaml resolves the
tag via `git rev-list -n 1`, so the tag must be a real
commit on the branch — `-dirty` tags can't be resolved and
were only ever valid on developer workstations.

cd750e8 is the pin-bump commit that wires the cluster to
upstream cardano-node-clients @ 4fca187 (CI-green head of
PR #94). publish-images will check out cd750e8 and build
components/tx-generator/.#docker-image at that source.

* Bump cardano-node-clients flake input from 2714a2f
  (pre-lint-fix) to 4fca187, the current green head of
  https://github.com/lambdasistemi/cardano-node-clients/pull/94.
* nix flake update cardano-node-clients regenerated the
  lockfile.
* docker-compose tag bumped to match the freshly-built
  image: 9f91d6f-dirty.

Locally re-validated end-to-end on the cluster:
* Refill landed (txId 5a9bef34..., 5000 ADA at addr_0,
  awaited=false due to chain-sync catch-up race).
* After 30 s of chain-sync settle: snapshot shows
  populationSize=1, p50=5000 ADA.
* Next transact succeeded (src=0, fresh_count=3,
  dsts=[1,2,0,3], values_lovelace summing to ~2.7 ADA).

The transient "no-pickable-source" responses while the
indexer catches up to a freshly-submitted tx are the
documented eventual-consistency behavior; the composer's
exit-1-on-not-applicable pattern absorbs them.

HttpEventSink::emit and HttpStatsSink::emit each spawned a fresh tokio
task per event, with no bound on in-flight tasks. Under heavy event
load (e.g. once the TxSubmission codec fix made tx propagation actually
work), spawn rate exceeded drain rate and tasks accumulated unboundedly,
each pinning a JSON payload, a reqwest::Client clone, and the in-flight
POST future.

Switch the EventSink/StatsSink traits to async (#[async_trait]) and
have HTTP sinks .await the POST inline. record() and emit_stats() are
now async; record_network_event() too. A slow aggregator now backpressures
the caller chain naturally instead of leaking spawned tasks.

New regression test (http_event_sink_does_not_spawn_per_emit) sanity-checks
that emit doesn't leave background tasks behind.

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