binding-mcp-kafka: topic administration (create_topics, delete_topics)

[jfallows]

Summary

Sub-issue of #1671. Adds admin tools for topic lifecycle management:

• create_topics → KafkaRequestBeginEx/createTopics + KafkaResponseBeginEx/createTopics
• delete_topics → KafkaRequestBeginEx/deleteTopics + KafkaResponseBeginEx/deleteTopics

See input/output schemas in the "Topic management" section of #1671.

Dependencies

None — createTopics/deleteTopics already exist in binding-kafka. Ready to build.

Notes

Mutating/admin-risk tools — keep this PR scoped narrowly to these two tools so the diff is reviewable on its own, separate from the read-only topic-metadata tools (tracked in a separate sub-issue since those need a binding-kafka prerequisite).