Update proof-of-means to 507,43 EUR, add announcement page, European number format (EN)

- Update the residence-permit "sufficient means" figure to 507,43 EUR/month
  (Slovenian basic minimum income from 1 April 2026, source gov.si) across the
  guide, FAQ, budget note, sample parent statement and my-route tip; replaces
  the old 484,88 everywhere.
- New standalone news announcement page /<lang>/news/proof-of-means-updated-2026/
  (trilingual), published 1 August 2026, with a clickable gov.si source box and a
  hero image (Pixabay, credited). news.js now supports announcement items
  (slug + body) and shows them newest-first on the homepage and News hub; the
  image doubles as the card thumbnail. Optimised 6.98MB to 255KB.
- Switch English EUR amounts to European format (comma decimal, dot thousands):
  507,43 / 9.600 / 1.000 etc. Only euro-prefixed amounts are touched, so SI/MK
  (which use a euro suffix) are unaffected. New generator eurofmt.js.

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

si/student-welcome-guide/student-budget/index.html

@@ -224,7 +224,7 @@
                     </table>
                 </div>
 
-                <p>Upoštevajte, da je pogoj sredstev za dovoljenje za prebivanje (ob zadnjem preverjanju okoli 484,88 EUR na mesec) blizu spodnjega dela tega razpona, zato je to pravni minimum za dokazovanje, ne udoben življenjski proračun. Načrtujte nad njim.</p>
+                <p>Upoštevajte, da je pogoj sredstev za dovoljenje za prebivanje (okoli 507,43 EUR na mesec od 1. aprila 2026) blizu spodnjega dela tega razpona, zato je to pravni minimum za dokazovanje, ne udoben življenjski proračun. Načrtujte nad njim.</p>
 
                 <h2>Proračun prvega meseca</h2>