Add Support for Valkey 9

[jeremyprime]

Summary

Add Valkey 9.x to the CI test matrix and address compatibility issues found during testing.

Issues found

Category	Error Count	Cause
Jedis 7 BITOP serialization	~48	Jedis/Lettuce send BITOP args in format Valkey 9 rejects
Stream DeletionPolicy	~15	Redis 8.0 feature (XADD/XTRIM with delete policy) not in Valkey
GLIDE CLUSTER SETSLOT	1	Valkey 9 rejects "Target node is myself", passes on 8.x

Tasks

• Add Valkey 9.x to CI matrix
• Gate BITOP and DeletionPolicy tests with @EnabledOnCommand or version check
• Investigate GLIDE CLUSTER SETSLOT behavior change on Valkey 9