Support 301/302 Redirects for Language-Prefixed Help Center URLs to Prevent Duplicate Indexing

When per-language settings are enabled in the Help Center, articles are accessible via both language-prefixed and non-prefixed URL structures (e.g., /articles/... and /en/articles/...).

Currently, both versions return HTTP 200 with identical content, which can lead to duplicate indexing in search engines—even if canonical tags point to the language-prefixed version.

This behavior may split ranking signals, impressions, and backlink equity across duplicate URLs, negatively impacting SEO performance.

Instead, only one URL variant should return HTTP 200, and the alternate variant should 301 (or 302) redirect directly to the designated locale-specific URL (e.g., /articles/... → /en/articles/..., or vice versa).

This ensures a single authoritative, indexable URL per article per locale while consolidating ranking signals and preserving backlink equity.