Shared schemas and primitives for Dynamo data generation.
The crate hosts the Mooncake replay JSONL schema and helpers, plus the
Dynamo request-trace loader and transient lowering used to build mocker
replay models in memory. Direct Dynamo request-trace replay does not write
an intermediate Mooncake file; the opt-in dynamo-bench exporter writes
one when needed. Shared row types keep trace producers and consumers in
lockstep.