Legal Analysis: full language follow-through (UI + LLM)

The tool now respects the chosen UI language end-to-end — even if the
source document is Norwegian, a user on EN/UK/PL gets the analysis in
their language. Norwegian statute references (barnevernsloven § 4-25,
EMK Art. 8) and case names (Strand Lobben mot Norge 37283/13) are kept
verbatim because they are proper nouns.

LLM (LegalAnalysisAgent.php):
- extractIssues: prompt asks for question + brief_context in user's
  language; statute refs preserved
- answerIssue: Norwegian core system prompt (keeps fine-tune precision)
  + language-coercion line for non-NO; localised context/source labels
- synthesise: overall_assessment, next_steps, disclaimer in user's
  language; explicit per-language disclaimer text
- runFullAnalysis empty-case fallback also localised
- what_to_check translated per language

UI:
- 40 new la_* translation keys in i18n.php × 4 languages (NO/EN/UK/PL)
- legal-analysis.php: 4-way lang switcher, dbnToolsT() for every label,
  emits window.DBN_LA_I18N for runtime JS strings
- legal-analysis.js: t() helper reads from window.DBN_LA_I18N
- layout_footer.php: emits window.DBN_CURRENT_LANG +
  window.DBN_ADDON_I18N so the legal-analysis add-on button works in
  the page's language no matter which tool it's invoked from
- tools.js add-on: reads from DBN_ADDON_I18N, passes DBN_CURRENT_LANG
  to /api/legal-analysis.php so server responds in same language

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

includes/layout_footer.php

@@ -23,6 +23,37 @@
 </main><!-- /appShell -->
 <?php require_once __DIR__ . '/footer.php'; ?>
 <link rel="stylesheet" href="/assets/css/doc-picker.css">
+<?php
+// Expose current UI language + add-on i18n map for tools.js (legal-analysis add-on
+// can fire from any tool page, so it needs strings without depending on per-tool maps).
+$_footerLang = $uiLang ?? dbnToolsCurrentLanguage();
+$_footerAddonI18n = [
+    'addonButton'      => dbnToolsT('la_addon_button',      $_footerLang),
+    'addonButtonBusy'  => dbnToolsT('la_addon_button_busy', $_footerLang),
+    'addonSection'     => dbnToolsT('la_addon_section',     $_footerLang),
+    'pass1'            => dbnToolsT('la_pipeline_pass1',    $_footerLang),
+    'pass2'            => dbnToolsT('la_pipeline_pass2',    $_footerLang),
+    'pass3'            => dbnToolsT('la_pipeline_pass3',    $_footerLang),
+    'pass1Extracting'  => dbnToolsT('la_pass1_extracting',  $_footerLang),
+    'pass1Found'       => dbnToolsT('la_pass1_found',       $_footerLang),
+    'pass2Asking'      => dbnToolsT('la_pass2_asking',      $_footerLang),
+    'pass2Answered'    => dbnToolsT('la_pass2_answered',    $_footerLang),
+    'pass3Synthesis'   => dbnToolsT('la_pass3_synthesis',   $_footerLang),
+    'waiting'          => dbnToolsT('la_waiting',           $_footerLang),
+    'searchingCorpus'  => dbnToolsT('la_searching_corpus',  $_footerLang),
+    'askingFinetune'   => dbnToolsT('la_asking_finetune',   $_footerLang),
+    'overall'          => dbnToolsT('la_overall',           $_footerLang),
+    'nextSteps'        => dbnToolsT('la_next_steps',        $_footerLang),
+    'answerHeader'     => dbnToolsT('la_answer_header',     $_footerLang),
+    'legalBasis'       => dbnToolsT('la_legal_basis',       $_footerLang),
+    'errorPrefix'      => dbnToolsT('la_error_prefix',      $_footerLang),
+    'serverReturned'   => dbnToolsT('la_server_returned',   $_footerLang),
+];
+?>
+<script>
+    window.DBN_CURRENT_LANG  = <?= json_encode($_footerLang) ?>;
+    window.DBN_ADDON_I18N    = <?= json_encode($_footerAddonI18n, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES | JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_QUOT | JSON_HEX_AMP) ?>;
+</script>
 <script src="assets/js/tools.js" defer></script>
 <?php if (!empty($extraScripts) && is_array($extraScripts)): foreach ($extraScripts as $extraScript): ?>
 <script src="<?= htmlspecialchars((string)$extraScript) ?>" defer></script>