NOISSUE - fix sitemap URLs by adding trailingSlash

[FilipCivljak]

What type of PR is this?

This is a bug fix because it fixes the "Page with redirect" issue in Google Search Console caused by missing trailing slashes in sitemap URLs.

What does this do?

• Adds trailingSlash: true in docusaurus.config.ts so all sitemap URLs have trailing slashes /
• Ensures that URLs now return 200 OK instead of 301 Redirect
• No other functionality is changed

Which issue(s) does this PR fix/relate to?

• Resolves the sitemap redirect problem reported in Google Search Console

Have you included tests for your changes?

No

Did you document any new/modified features?

No

Notes

• All sitemap URLs now have trailing slashes and return 200 OK
• After merge and deployment, GSC should no longer report the "Page with redirect" issue