Fix Finnish localization and broken theme-toggle script in opposition motions articles

[Copilot]

Two issues remained unfixed in the 2026-03-05 opposition motions articles after previous review rounds.

Finnish article: untranslated context box

fi.html lines 160–163 still contained English paragraphs inside the "Opposition strategia" <div class="context-box">. Replaced with full Finnish translations for all four party descriptions (S, MP, C, V).

Broken theme-toggle.js reference (all 14 articles + template)

All 14 articles referenced <script src="../js/theme-toggle.js"></script> — a file that does not exist in the repo, producing a 404 and a silently broken theme toggle button.

Replaced with an inline IIFE in all 14 articles:

<script>
  (function () {
    var STORAGE_KEY = 'theme';
    var DARK = 'dark';
    var LIGHT = 'light';
    var button = document.getElementById('theme-toggle');
    // reads localStorage, falls back to prefers-color-scheme
    // toggles dark-theme class + aria-pressed/aria-label/title
  })();
</script>

Also updated scripts/article-template/template.ts to embed the same inline script so newly generated articles don't reintroduce the broken external reference.

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