Cardano Updates

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

The datum payload (PlutusData) and the witness set are common worker
inputs — bring them back into the trimmed schema. Both were
wire-stable across utxorpc-spec 0.17 -> 0.18, so the converter just
roundtrips them via prost.

New types in cardano.rs: Datum, PlutusData (+ Constr, PlutusDataPair,
PlutusDataMap, PlutusDataArray, BigInt), Script (+ NativeScript,
NativeScriptList, ScriptNOfK), WitnessSet, VKeyWitness.

Tags on PlutusData and Constr.any_constructor match upstream 0.17
verbatim (verified by failing-then-fixing wire_compat tests).

asteria-tracker example restores its datum-derived position tracking.

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

Drop everything from cardano.rs except the wire surface workers
actually consume:

  TxOutput { address, coin, assets }
  Tx       { inputs, outputs, fee, hash }
  TxInput  { tx_hash, output_index, as_output }
  Multiasset, Asset (output_coin only)

Tags absent from these structs (datum, script, certificates,
withdrawals, mint, witnesses, validity, auxiliary, proposals, ...) are
deliberately dropped — workers needing them must extend the schema and
the converter explicitly. This shrinks balius-proto from ~5400 LOC of
generated cardano + 14k LOC of pbjson serde to 181 LOC total.

Block/BlockBody/BlockHeader move out of balius-proto since they never
cross WIT. The runtime's Block enum reverts to wrapping
utxorpc::spec::cardano::Block; per-Tx conversion happens at apply_block
/ undo_block via the fallible Block::txs() accessor.

PParams gone too: the SDK txbuilder now defines a minimal
PParams { coins_per_utxo_byte: u64 } locally, and the runtime's
read-params emits a matching minimal JSON shape.

asteria-tracker example trimmed to use only multiasset fields (datum-
derived position is dropped since the datum tag is gone).

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