docs(i18n): explain translation contribution entry points

Document the translated README and website PO contribution entry points. Resolve README filenames through the existing locale inventory, preserving canonical Korean README links.

Validated on Linux with docs:check, five README consistency tests, all 20 inventory README paths, and current-head CI/automated reviews.

CONTRIBUTING.md

@@ -258,6 +258,23 @@ The separate GitHub Pages host uses only the manual
 **Settings → Pages → Build and deployment → Source** must be set to
 **GitHub Actions** before deploying there.
 
+### Translation corrections
+
+README editions and website editions have separate translation sources:
+
+- Find the language's `readme` path in the
+  [language inventory](website/locales/languages.json) and edit that file.
+  Locale codes and README suffixes can differ. Use the
+  [English README](README.md) to check commands, requirements, and analysis claims.
+- Edit `msgstr` values in `website/locales/<language>/messages.po` for website
+  text. Follow the [website translation guide](website/locales/README.md) for
+  the Python environment, catalog validation, and local preview. Preserve source
+  strings, contexts, placeholders, commands, paths, and recorded evidence.
+
+Before submitting a website translation, run the catalog and website checks in
+that guide. Translated HTML in `website/_site/` is generated; edit the PO catalog
+rather than the generated pages.
+
 ## Development feedback and PR verification
 
 For routine merges, wait for the required checks to pass for the current PR