Add changelog 4.17.0-alpha.1

Editor assessment

The subject is complete for its kind — the 4.17.0-alpha.1 changelog is added, version identified — and the body is a short squash-merge bullet list (`Update CHANGELOG.zh-CN.md`, `docs: update`) that adds nothing substantive. Type `docs` is correct; scope is unnecessary for changelog content. Footers are absent beyond the PR reference, and none are needed. Style is clean — no trailing period, short subject, no junk. As with all changelog commits the real content lives in the diff, so the message is clear and honest, but with no summary of the release highlights and a boilerplate body, its stand-alone teaching value is mediocre rather than good.