Add RandomizedElectionTimeout() method to RaftNode returning TimeSpan in
[ElectionTimeoutMinMs, ElectionTimeoutMaxMs) using TotalMilliseconds (not
.Milliseconds component) to prevent synchronized elections after partitions.
Make Random injectable for deterministic testing. Fix SendHeartbeatAsync stub
in NatsRaftTransport and test-local transport implementations to satisfy the
IRaftTransport interface added in Gap 8.7.
- Add SnapshotChunkEnumerator: IEnumerable<byte[]> that splits snapshot data
into fixed-size chunks (default 65536 bytes) and computes CRC32 over the
full payload for integrity validation during streaming transfer
- Add RaftInstallSnapshotChunkWire: 24-byte header + variable data wire type
encoding [snapshotIndex:8][snapshotTerm:4][chunkIndex:4][totalChunks:4][crc32:4][data:N]
- Extend InstallSnapshotFromChunksAsync with optional expectedCrc32 parameter;
validates assembled data against CRC32 before applying snapshot state, throwing
InvalidDataException on mismatch to prevent corrupt state installation
- Fix stub IRaftTransport implementations in test files missing SendTimeoutNowAsync
- Fix incorrect role assertion in RaftLeadershipTransferTests (single-node quorum = 1)
- 15 new tests in RaftSnapshotStreamingTests covering enumeration, reassembly,
CRC correctness, validation success/failure, and wire format roundtrip
