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>

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

@@ -224,7 +224,7 @@
                     </table>
                 </div>
 
-                <p>Note that the residence-permit means requirement (around €484.88 per month at the last check) sits near the lower end of this range, so it is a legal minimum to prove, not a comfortable living budget. Plan above it.</p>
+                <p>Note that the residence-permit means requirement (around €507,43 per month from 1 April 2026) sits near the lower end of this range, so it is a legal minimum to prove, not a comfortable living budget. Plan above it.</p>
 
                 <h2>First-month budget</h2>