feat(website): deploy docs to Zephyr Cloud

[Nsttt]

Motivation

Deploy the Rstack CLI documentation through the standalone Zephyr website workflow while keeping normal local docs development and builds free of authentication and deployment side effects.

Changes

Enable the Zephyr plugin only when deploy-website.yml sets ZEPHYR_DEPLOY=true. Keep website deployment out of the npm release workflow. Use published zephyr-rspress-plugin@1.4.2, which waits for configured plugins' afterBuild hooks before collecting upload files, so the sitemap plugin remains in the ordinary plugin list.

Pin the six Zephyr SDK packages' release-age exceptions to exactly 1.4.2 so this fresh release can be installed without weakening the policy for other versions. The site org remains rstack; the local package link and temporary live-test org are removed.

Validation

pnpm check, a frozen-lockfile install, credential-free pnpm doc:build, and docs development with all ZE_*/ZEPHYR_* environment variables removed passed. English and Chinese dev routes returned HTTP 200 with no Zephyr activity.

The published 1.4.2 package also completed a real deployment in a temporary test organization, with authentication and upload enabled. Its deployed sitemap.xml returned HTTP 200, contained 44 URLs, and matched the local output byte-for-byte. The intended rstack org was not used for this live test; CI still needs ZE_CI_TOKEN with access to that site. Pre-commit Codex autoreview completed with no actionable findings.

[chenjiahan]

It looks like we don't need to trigger website deployment from the release workflow. The standalone Deploy Website workflow should be sufficient. Could we remove the website deployment job from release.yml and keep deployment in deploy-website.yml?

[chenjiahan]

Two additional issues with the Zephyr integration:

[Nsttt]

@chenjiahan Fixed in 78a2b24. Removed the website deployment job and its release-SHA plumbing from .github/workflows/release.yml; the workflow now matches the PR base. Website deployment stays in .github/workflows/deploy-website.yml.

The two inline concerns are addressed as well: local docs commands omit Zephyr unless the deployment flag is set, and the PR now uses published zephyr-rspress-plugin@1.4.2 with the sitemap ordering fix. I verified a real deployment in a temporary test organization and fetched a 44-URL sitemap that matched the local build byte-for-byte.