- Add Prompt model with template variable rendering ({{var}} syntax)
- Add gRPC and HTTP transport for Prompt queries (QueryPromptRequest/Response)
- Add AiHttpClientProxy for HTTP-based AI operations (GET /v3/client/ai/prompt)
- Add PromptCacheHolder with MD5 conditional polling and change notification
- Add PromptSubscribeManager for prompt change subscriptions
- Support transport mode selection via ClientConfig.ai_transport_mode (grpc/http)
- Register QueryPromptResponse in GrpcUtils.remote_type
- Bump version to 3.2.0b1