Fix .ts→.js script reference and translate untranslated English content in Chinese article

[Copilot]

All 14 opposition-motions article pages referenced back-to-top.ts directly — browsers can't execute TypeScript, so the module silently failed on every language page. The Chinese (zh) article also contained large English-only blocks in the article lede, opposition strategy section, all 20 "Why it matters" paragraphs, coalition dynamics party names, and the "What happens next" paragraph, contradicting the stated no-untranslated-spans guarantee.

Changes

• Script fix (all 14 files) — back-to-top.ts → back-to-top.js

  <!-- before -->
  <script type="module" src="../scripts/back-to-top.ts"></script>
  <!-- after -->
  <script type="module" src="../scripts/back-to-top.js"></script>

• Chinese translations (zh only) — Translated to Chinese:

  • article-lede paragraph under 反对党动议
  • Full opposition strategy context-box (four party descriptions)
  • All 20 为何重要 (Why it matters) paragraphs
  • Coalition dynamics party name labels (Social Democrats (S) → 社会民主党（S） etc.)
  • 接下来会发生什么 (What happens next) paragraph

Swedish official motion titles in <h3> headings are intentionally retained in Swedish — they are official government document references, consistent with all other language versions including English.

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.