add golang admin sdk

[skyrover001]

close #2221

我已确认该 PR 已自测通过，相关截图如下：

[Copilot]

Pull Request Overview

This PR introduces a Golang SDK along with sample usage documentation, API client implementations, chat functionality, and controller updates for token management. Key changes include:

• New usage instructions and examples in the readme.
• Implementation of various API endpoints (user, token, channel, log) and a client to interface with them.
• Updates to the controller for handling token operations with role-based logic.

Reviewed Changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
sdk/readme.md	Added documentation on how to install, initialize, and use the SDK.
sdk/main.go	Provided sample usage for testing API endpoints of the SDK.
sdk/chat/chat.go	Introduced chat functionality using HTTP streaming.
sdk/api/*.go	Implemented API methods for users, tokens, logs, channels, and client.
controller/token.go	Updated token controller to support role-based token operations.

Comments suppressed due to low confidence (1)

controller/token.go:249

• In the UpdateToken handler, the logic for root users may not correctly set the userId when token.UserId is 0. Consider revising this condition to ensure that the correct user context is maintained.

if token.UserId == 0 { userId = token.UserId }