feat: Legal Tools v1 — multilingual landing, dashboard, SSO bridge

- Public landing page at / for unauthenticated users (EN/NO/UK/PL)
- Authenticated / shows Case Workbench dashboard with manifesto strip,
  stats, and launched-tool grid (Transcribe, Timeline, BVJ, Advocate,
  Deep Research, Corpus)
- Added includes/i18n.php with full 4-language translation layer
- Extended layout.php to Case Workbench shell with tool rail, lang switcher
- AI output language normalization extended to en/no/uk/pl in PHP agents
- SSO token validation in bootstrap.php / index.php (dobetternorge.no bridge)

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

includes/bootstrap.php

@@ -107,6 +107,7 @@ function dbnToolsStartSession(): void
 }
 
 dbnToolsStartSession();
+require_once __DIR__ . '/i18n.php';
 
 function dbnToolsIsAuthenticated(): bool
 {
@@ -224,8 +225,7 @@ function dbnToolsJsonInput(int $maxBytes = 50000): array
 
 function dbnToolsNormalizeLanguage(mixed $value): string
 {
-    $language = strtolower(trim((string)$value));
-    return in_array($language, ['no', 'en'], true) ? $language : 'en';
+    return dbnToolsNormalizeUiLanguage($value);
 }
 
 function dbnToolsNormalizeRegion(mixed $value): string
@@ -472,10 +472,13 @@ function dbnToolsHasActiveSubscription(int $clientId, int $packageId, ?PDO $db =
 
 function dbnToolsDisclaimer(string $language): string
 {
-    if ($language === 'no') {
-        return 'Juridisk informasjon og forberedelsesstøtte, ikke endelig juridisk rådgivning.';
-    }
-    return 'Legal information and preparation support, not final legal advice.';
+    $language = dbnToolsNormalizeUiLanguage($language);
+    return match ($language) {
+        'no' => 'Juridisk informasjon og forberedelsesstøtte, ikke endelig juridisk rådgivning.',
+        'uk' => 'Юридична інформація та підтримка підготовки, не остаточна юридична порада.',
+        'pl' => 'Informacje prawne i wsparcie przygotowania, nie ostateczna porada prawna.',
+        default => 'Legal information and preparation support, not final legal advice.',
+    };
 }
 
 function dbnToolsExcerpt(string $text, int $limit = 520): string