fix(client): release owned HTTP resources

[GregHolmes]

Summary

• make DeepgramClient and AsyncDeepgramClient AutoCloseable
• release the dispatcher and connection pool only when the SDK created the OkHttpClient
• preserve caller ownership when .httpClient(...) supplies the client
• make every streaming disconnect() terminal and safe before, during, and after connection setup
• synchronize connection teardown, cancellation, and socket publication so no late socket survives cleanup
• complete in-flight connect() futures exceptionally when teardown wins the handshake race
• close all streaming example resources on success and failure paths
• document ordered parent-client and WebSocket cleanup with try-with-resources

Validation

• ./gradlew spotlessCheck test compileExamples --rerun-tasks
• Manual production Flux probe: connected a Listen v2 socket, disconnected it, then closed the parent client. The child JVM exited in 772 ms.

Closes #104

[GregHolmes]

Superseded by #108, which keeps the ownership-aware client lifecycle fix focused. Generated WebSocket teardown races and streaming-sample cleanup are tracked separately in #107.