docs(i18n): fix stale RL training links

[Monrother]

What does this PR do?

Fixes stale Simplified Chinese documentation links that still pointed at the removed rl-training feature page.

• Replaces the zh-Hans feature overview RL Training entry with the current Batch Processing entry.
• Syncs the zh-Hans learning path with the current English docs.
• Uses the external Atropos environments link and removes the stale RL Training feature row.

Related Issue

N/A

Type of Change

• Documentation update

How to Test

1. Confirmed no open duplicate PRs or issues for rl-training zh-Hans.
2. Verified no internal rl-training page references remain in website/i18n/zh-Hans or website/docs.
3. Ran: npx docusaurus build --locale zh-Hans
   • Result: exit 0. Existing unrelated broken-link and anchor warnings remain outside this change.
4. Checked the rendered learning-path and feature-overview HTML pages contain the replacement links and text.

Checklist

• Read the Contributing Guide
• Conventional Commit used
• Focused docs-only change
• Tested on Windows 11 / PowerShell
• No pytest added because this is documentation-only

[alt-glitch]

This was generated by AI during triage.

Duplicate of #69157: both make the same two zh-Hans documentation changes for the stale RL-training links. #57919 and #53274 remain related alternatives with broader or conflicting documentation policy.

[Monrother]

Thanks for the heads-up. I confirmed that #69157 covers the same two zh-Hans documentation changes. I will close this PR as a duplicate. I will also check existing open and merged PRs before starting future changes.

[Monrother]

Closing as a duplicate of #69157.