Add the dobj-trade demo

CLAUDE.md

@@ -24,6 +24,7 @@ The workspace is declared in `Cargo.toml`. Crate-by-crate:
 | `sdk`                            | Rhai engine + two-phase Loader/Executor that compiles plugin scripts into pod2 modules.                                                                                                              |
 | `txlib`                          | Transaction state machine: `StateHeader`, `GroundingWitness`, `Tx`, `TxBuilder` + `TxFinalized` rule. Accepts local object dictionaries or statements supplied by another party; does not model party identities. |
 | `joint-tx`                       | Multi-party transaction planning: validates participants and custody, derives the shared `TxPlan` and proving schedule, and exchanges proof contributions. Depends on `txlib`.                    |
+| `interfaces/trade`               | Two-party swap CLI over iroh and `joint-tx`: loads local objects and plugins, proves in process, posts through the relayer, and imports the received object through dobjd.     |
 | `synchronizer`                   | Long-running service: ingests Ethereum blobs, maintains Merkle state, serves HTTP queries.                                                                                                           |
 | `relayer`                        | HTTP service that wraps proofs as EIP-4844 blob txs and submits them.                                                                                                                                |
 | `archiver`                       | Service that follows beacon blocks and archives blobs filtered by destination address to the filesystem (no DB). Serves them via a beacon-compatible HTTP API; the synchronizer reads blobs from it. |