This release adds a non-blocking interface to the receiver state machine. Every step that previously required a synchronous validation closure is now split in two: a method that extracts the data to be checked, and a
method that submits the results and advances the typestate. Wallets whose signing, broadcast checks, or ownership lookups are asynchronous, or that live in a separate process from the code driving the session, can now drive both the v1 and v2 receiver flows without blocking. The existing callback methods remain as convenience wrappers, so this release is backward compatible.

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