Add Support MSOS page (EN/MK/SI) and wire the header button

New donation/partnership landing page telling the MSOS story of being
community-built: hero, "built by the community" narrative, four ways to
support (partner/sponsor, donate, offer skills/space, spread the word),
"where your support goes" impact, a bank-transfer card (placeholder IBAN/
bank/SWIFT for the org to fill in), a partners thank-you marquee, and a
contact CTA (mailto info@msosorg.com). New css/pages/_support.css.

The header "Support MSOS" button (previously a dead <button>) now links to
/{lang}/support/ on all pages. SEO block + hreflang + sitemap regenerated.

MK/SI translations are AI-drafted -> native review. Bank details are
placeholders pending real IBAN/SWIFT.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

css/main.css

@@ -36,4 +36,5 @@
 @import 'pages/_faq.css';
 @import 'pages/_blog.css';
 @import 'pages/_news.css';
-@import 'pages/_member.css';
+@import 'pages/_member.css';
+@import 'pages/_support.css';