refactor: switch admin create_queue from protobuf to binary encoding - #7

Summary

• Update FibpAdminClient test helper from hand-encoded protobuf to binary wire format
• Replace writeVarint with writeU16/writeU32 helpers for binary encoding
• encodeCreateQueueRequest now produces queue_len:u16 + queue + on_enqueue_len:u16 + on_failure_len:u16 + visibility_timeout_ms:u32

Test plan

• ./gradlew compileJava compileTestJava passes (verified locally)
• Integration tests pass against a FIBP server with binary admin encoding (PR #153)
• No protobuf encoding remains in test infrastructure

Summary by cubic

Switch the test FibpAdminClient CreateQueue request from hand-rolled protobuf to the binary wire format. Aligns admin tests with the server’s binary encoding, removes protobuf from test code, and adds UTF-8 length validation to prevent u16 overflow.

• Refactors

  • Encode CreateQueue as: queue_len:u16 + queue:utf8 + on_enqueue_len:u16 + on_enqueue:utf8 + on_failure_len:u16 + on_failure:utf8 + visibility_timeout_ms:u32.
  • Replace varint writer with writeU16 and writeU32.

• Bug Fixes

  • Validate queue name UTF-8 length (<= 65535); throw IOException if exceeded.

^{Written for commit bb8683f. Summary will update on new commits.}