docs: align scheduler API examples

[RerankerGuo]

Fixes #2083.

Summary

• Replace scheduler docs Quick Start snippets that called missing SDK methods with direct requests calls to the documented scheduler HTTP endpoints.
• Rename docs/cn/open_source/open_source_api/scheduler/ wait.md to wait.md.

Validation

• python3 static docs check: confirmed the leading-space file is gone, wait.md exists, stale SDK method names are absent, and scheduler endpoint paths are present.
• make format could not run locally because poetry is not installed: make: poetry: Command not found.

[shinetata]

Thanks for the contribution! The scheduler documentation issue has already been addressed by #2113 and is now available on main via #2119.

The merged fix covers the same two documentation files, including the HTTP examples and the wait.md rename, with a few additional response-handling improvements. Since this PR is now conflicting and fully superseded, we’re closing it to avoid duplicate changes.

Thanks again for helping identify and fix #2083.