Make blog.ubik.hr blog-only: redirect non-blog pages to ubik.hr

[lukaskywalk]

Summary

The Hugo deploy at `blog.ubik.hr` was originally the entire ubik.hr website. After the migration to Gatsby (now serving ubik.hr), this repo was repurposed to host only `/blog/`, but the navbar and the old non-blog pages (members, contact, arbitration, consulting, become-a-member) were left in place — so visitors clicking the navbar landed on stale 2024 content.

This PR makes `blog.ubik.hr` truly blog-only:

1. Updates the navbar (HR + EN) so all non-blog links point to https://ubik.hr (absolute URLs).
2. Adds redirects on every non-blog section page so anyone arriving via direct URL or search engine gets sent to the corresponding ubik.hr page.

URL mapping

Old (blog.ubik.hr)	New target (ubik.hr)
`/members/`, `/en/members/`	`/members/`, `/en/members/`
`/contact/`, `/en/contact/`	`/contact/`, `/en/contact/`
`/arbitration/`, `/en/arbitration/`	`/arbitraza/`, `/en/arbitraza/`
`/become-a-member/`, `/en/become-a-member/`	`/join/`, `/en/join/`
`/consulting/`, `/en/consulting/`	`/` (Gatsby has no consulting page)

Changes

• `site/config.toml` — navbar URLs (HR + EN) updated to absolute ubik.hr links; `/blog/` stays relative
• `site/content/{croatian,english}/{members,contact,arbitration,consulting,become-a-member}/_index.md` — replaced with redirect front-matter (`type: redirect`, `redirect_to: ...`, `sitemap_exclude: true`)
• `site/layouts/_default/redirect.html` and `site/layouts/redirect/list.html` — new template emitting:
  • ``
  • ``
  • ``
  • JS `window.location.replace` fallback

Out of scope (intentional)

• The Hugo home page at `blog.ubik.hr/` is left as-is. Decide separately whether it should redirect to `ubik.hr/` or to `blog.ubik.hr/blog/`.
• Individual member detail pages (e.g. `/members/luka-sucic/`) are not redirected — only section landing pages. Open a follow-up if you want those handled too.

Backups

Before this PR, the state was tagged for permanent recovery:

• `backup/pre-blog-cleanup` — master source
• `backup/built-site-pre-cleanup` — built gh-pages site

Test plan

• Workflow run succeeds
• Click "Members" / "Contact" / "Arbitraža" / "Postani član" in navbar at `blog.ubik.hr` → lands on the corresponding ubik.hr page
• Direct visit `https://blog.ubik.hr/members/\` → redirects to `https://ubik.hr/members/\`
• Same checks for `/en/` variants
• `https://blog.ubik.hr/blog/\` still works
• No regressions in blog post rendering

🤖 Generated with Claude Code