Interface EscrowTransferActivityDependencies

Activities that mutate escrow transfer state. Every mutating activity is idempotent: it reads the row + the on-chain EscrowState PDA, derives the effective state, and short-circuits if the work has already happened on a prior container.

The set is deliberately small — each one performs a single DB or chain action so workflows can compose them point-to-point.

NOTE(nonce serialization): the nonce column is bigint in the DB. Temporal's default JSON data converter can't serialize JS bigints, so we exchange nonce as a base-10 string at the activity boundary and BigInt(...) it inside the activity body / workflow as needed.