[DEV-1270] Support atomic cross-stream consistency validation when appending events

[w1am]

Adds the appendRecords operation, which allows appending events to one or more streams in a single atomic transaction similar to multiStreamAppend, but with two key differences:

• Interleaved ordering: Records from different streams can be mixed freely, and their exact order is preserved in the global log.
• Decoupled consistency checks: You can validate the state of any stream before the transaction commits, even streams you're not writing to. This makes it possible to enforce business rules that span multiple streams in a single round-trip.

[linear]

DEV-1270 Java | Support atomic cross-stream consistency validation when appending events

[github-actions]

@w1am 👉 Created pull request targeting release/v1.2: #383