KIP-791 — Add Record Metadata to StateStoreContext

Accepted Kafka 3.2 Streams

Adds `recordMetadata()` to the `StateStoreContext` public interface so state stores can access the source record's offset and partition metadata during processing. `AbstractProcessorContext` already implements this method internally, but it is not exposed through the `StateStoreContext` interface, preventing stores from implementing Read-Your-Writes consistency or offset tracking.

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