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-work/index.html

@@ -203,7 +203,7 @@
 
                 <h2>Minimum rate and deductions</h2>
 
-                <p>From 5 February 2026, the minimum gross hourly rate is €8.98, and the reference resident net rate after the standard pension contribution is €7.73. A tax non-resident may initially have a 13.95% pension and disability contribution and a 22.5% income-tax advance. The exact net amount depends on tax residence, treaty relief, payment size, and approved claims.</p>
+                <p>From 5 February 2026, the minimum gross hourly rate is €8,98, and the reference resident net rate after the standard pension contribution is €7,73. A tax non-resident may initially have a 13.95% pension and disability contribution and a 22.5% income-tax advance. The exact net amount depends on tax residence, treaty relief, payment size, and approved claims.</p>
 
                 <h2>Treaty relief for Macedonian tax residents</h2>