docs: define repository and chat language policy

Author: Neikon

AGENTS.md

@@ -14,6 +14,8 @@ Operational notes:
 - Validate with `npm test` for `themes.json` checks.
 - Use `npm run build` when touching generated site assets or source files under `dev/`.
 - When automation changes are introduced, document the intent and impact in `MEMORY.md`.
+- Use English for repository-facing output by default, including code, comments, commit messages, pull request text, documentation, workflow messages, and user-facing project strings unless the repository already requires another language in a specific place.
+- In chat, always reply in the same language used by the user.
 - After implementing relevant changes or new functionality, create a commit and push it so work remains traceable and easy to roll back if needed.
 - Never perform a merge without explicit user authorization.
 - Never take actions that could affect the repository's production main branch without explicit user authorization.

MEMORY.md

@@ -49,6 +49,7 @@ This file stores durable project context so future conversations can resume work
 - Hidden config generation now filters non-`.txt` files explicitly so builds do not create stray files like `docs/.robots`
 - Theme entries that depended on fragile remote screenshots have been localized into `images/themes/remote-*` and now build into committed assets under `docs/assets/img/themes/`
 - Binary copies for static images now use `fs.promises.copyFile` instead of `gulp.src().pipe(dest())` because the stream path was corrupting some `.webp` assets in `docs/`
+- Project-facing text should be written in English by default; chat replies should mirror the user's language
 
 ## Architecture Snapshot