feat: Add `CLIENT KILL` command support

[currantw]

Summary

Add GLIDE-native CLIENT KILL command support to the Valkey GLIDE C# client.

Description

The CLIENT KILL command is supported by Valkey GLIDE core (request types ClientKillSimple / ClientKill) but is not yet implemented in the C# client.

StackExchange.Redis supports CLIENT KILL on IServer, but its signatures rely on SER-specific types (EndPoint, ClientKillFilter, ClientType) that are tightly coupled to SER's direct server connection model. SER compatibility is not feasible for this command — implement as GLIDE-native only.

Proposed Solution

Add CLIENT KILL methods to the GLIDE-native client interfaces and implement in GlideClient and GlideClusterClient. Refer to the other Valkey GLIDE clients (Java, Python, Go, Node) for signature conventions, option types, and return types.

Effort & Severity Estimates

• Effort: medium
• Severity: low

Related

• refactor: Connection management command API cleanup #275 — Connection management command API cleanup.
• refactor: Command API cleanup — StackExchange.Redis compatibility and cross-client consistency #270 — Parent issue: command API cleanup.

[currantw]

Note: This command is supported by Valkey GLIDE core but is not currently implemented by any of the Valkey GLIDE clients (Java, Python, Go, Node). It may make sense to coordinate implementation across all clients simultaneously rather than adding it to C# in isolation. Likely not an immediate priority.