PASS repeat returns same receipt and one effect
PASS changed amount rejected
PASS changed destination rejected
PASS changed currency rejected
PASS tenant-scoped keys
PASS invalid command rejected before write
PASS missing account rolls back receipt
PASS failure before commit rolls back effect and receipt
PASS lost response after commit permits safe retry
PASS 12 concurrent duplicate attempts produce one receipt
PASS 12 concurrent distinct operations lose no credits
PASS process halt before commit recovers with zero initial effect
PASS process halt after commit recovers with one initial effect
13 tests passed
