docs: language switcher is not working for English

[sarisia]

Description

In my environment opencode docs shows Japanese by default and when I select English from language switcher it wrongly shows Japanese page. Switching to other language (e.g. Italiano) works fine.

• Select Italiano shows https://opencode.ai/docs/it/
• Select English shows https://opencode.ai/docs/ but it's Japanese

Plugins

No response

OpenCode version

No response

Steps to reproduce

1. Open https://opencode.ai/docs/
2. Navigate to language switcher on bottom of page
3. Select English

Screenshot and/or share link

No response

Operating System

No response

Terminal

No response

[github-actions]

This issue appears to be a duplicate of existing issues reporting the same language switcher problem. Please check:

• /docs/en returns 404 in production and English selection reverts to previous non-English locale #13108: /docs/en returns 404 in production and English selection reverts to previous non-English locale
• [Website] Docs language switcher fails to update content to English #13078: Docs language switcher fails to update content to English (reported from Traditional Chinese)
• Language Switcher on opencode Website Does Not Seem to Work #13057: Language switcher not working when browsing in Simplified Chinese

All of these issues describe the same root cause: selecting English from the language switcher doesn't properly update the page content when your default locale is set to a non-English language (Japanese, Chinese, Korean, etc.).

Consider consolidating efforts on one of the existing issues to avoid duplicate work.

[Seungjun0906]

@jayair
I have PR for this issue #13109

[areai51]

#13449