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>

corpus.php

@@ -74,6 +74,8 @@ require_once __DIR__ . '/includes/layout.php';
         <div class="lang-pills" role="group" aria-label="Language">
             <button class="mode-pill is-active" data-lang="en" type="button">EN</button>
             <button class="mode-pill" data-lang="no" type="button">NO</button>
+            <button class="mode-pill" data-lang="uk" type="button">UK</button>
+            <button class="mode-pill" data-lang="pl" type="button">PL</button>
         </div>
     </div>
 </div>