Cardano Updates

Two distinct size guards on the receive path are now correctly
layered:

1. **Demuxer buffer cap** (DoS protection): fixed at protocol
   registration via `ProtocolConfig::ingress_limit`, never narrowed
   at runtime.  Sized to bound runaway accumulation when a protocol
   consumer falls behind.

2. **Codec per-message cap** (protocol conformance): `Runner::recv`
   passes `P::size_limit(state)` to `CodecRecv::recv`; after a
   CBOR value decodes, the consumed-bytes count is checked against
   the per-state spec limit and `MuxError::MessageTooLarge` is
   returned (and the connection torn down) for spec-violating peers.

The previous design conflated these — `Runner` overrode the demuxer's
buffer cap with the current state's per-message cap on every
transition, so a fast peer pipelining `MsgStartBatch` + `MsgBlock`
into one TCP read could legitimately overflow before the local
runner advanced the state.  Reverts `BlockFetch::size_limit` to spec
(`SIZE_LIMIT_SMALL` for StIdle/StBusy, `SIZE_LIMIT_STREAMING` for
StStreaming); the values are now actually enforced at decode time
rather than misused as buffer caps.

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

This renders RBs and EBs of the chain(s) observed on the event stream.

This uses the same typescript -> json schema workflow and also sanity
checks the prepared simulator traces in the repository.

The legacy tracer emitted TraceForgedBlock with a nested `forgedBlock`
wrapper at the top of the log line. After the prototype rebase against
the current cardano-node the tracer is exposed under tracing v2 as
`ns=Forge.Loop.ForgedBlock`, with the inner data flattened. Verified
against the proto-devnet Loki stream:

  {"block":"8ee35205...","blockNo":25,"blockPrev":"625d1f62...",
   "kind":"TraceForgedBlock","slot":753}

Switch the discriminator to the `ns` stream label and read the flat
`block` / `slot` fields. The Loki query (which matches on
"TraceForgedBlock") still matches the inner data, so the existing
subscription is unchanged.

size_bytes is no longer in this event — left as 0 with a TODO to
correlate against Forge.Loop.AdoptedBlock (which carries `blockSize`).