docs(i18n): align Chinese README entry points with English README

[alskme]

Closes #893

Summary

Updated README_zh-CN.md to align its navigation with the English README.

• Added links for the app, getting started, how it works, quickstart, documentation, contributing guide, and discussions.
• Clarified that the English README is the canonical source for GitHub collaboration and implementation details.
• Reworded the Quickstart link in Chinese.

Validation

• Verified that docs/quickstart.md exists.
• Verified that docs/onboarding-guide.md exists.
• Verified that CONTRIBUTING.md exists.
• Verified that the discussions link redirects to the current repository.
• No application code was changed.

[github-actions]

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[yuezengwu]

The Chinese README entry points are consistent with the English README. Local paths and Chinese heading anchors resolve, and the Discussions URL redirects to this repository.

Please fix the PR branch name before merge: the existing Check Branch Name job runs for every pull request and only accepts feat/, fix/, refactor/, test/, docs/, chore/, or merge/ (with a separate hub-session- exception). The current patch-1 branch matches neither condition. Executing the workflow's condition locally exits 1, so approving the queued CI run as-is will not clear this gate. Please use a compliant docs branch and retain the PR context when updating or replacing it.

Other merge gates: the CLA check currently fails because the contributor has not signed; please follow the CLA bot's instructions. CI run 37455736710 is waiting for maintainer approval, so remote CI has not executed yet.

Validation at commit 82ef687de8b540fdf5f819d549bc84c3b2a9560d, base 13f2a38b7b8a25789d4430b9dc968864b26611d1: pnpm check passed with existing warnings; pnpm typecheck passed (Turborepo cache hits). Runtime tests were omitted for this single-file documentation change. git diff --check reports an extra blank line at EOF in README_zh-CN.md:175; removing it is a minor cleanup.