Add My Documents panel to workbench + user-docs API

- api/user-docs.php: GET/DELETE shared dbn_user_docs table (SSO users only)
  connects to dobetternorge DB via DBN_DB_* env vars
- workbench.php: My Documents panel (section 05) for SSO/free-tier users;
  shows docs uploaded from either AI chat or tools, links to AI Chat for upload
- workbench.js: fetch + render doc list, delete with Qdrant cleanup
- tools.css: workbench-docs panel + item styles
- i18n.php: my_docs_* strings in all 4 languages

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

workbench.php

@@ -198,6 +198,24 @@ foreach ($evidenceFields as [$name, $label, $hint]):
             </label>
         </section>
     </form>
+
+<?php if (dbnToolsIsFreeTier()): ?>
+    <section class="workbench-panel workbench-panel--docs" aria-labelledby="workbenchDocsTitle"
+             data-my-docs="true">
+        <div class="workbench-section-head">
+            <p class="workbench-kicker">05</p>
+            <h2 id="workbenchDocsTitle"><?= htmlspecialchars(dbnToolsT('my_docs_title', $uiLang)) ?></h2>
+        </div>
+        <p class="workbench-docs__desc"><?= htmlspecialchars(dbnToolsT('my_docs_desc', $uiLang)) ?></p>
+        <div id="myDocsList" class="workbench-docs__list" role="list" aria-live="polite">
+            <p class="workbench-docs__loading"><?= htmlspecialchars(dbnToolsT('loading', $uiLang)) ?></p>
+        </div>
+        <a class="secondary-button workbench-docs__cta" href="https://ai.dobetternorge.no/" target="_blank" rel="noopener noreferrer">
+            <?= htmlspecialchars(dbnToolsT('my_docs_upload_cta', $uiLang)) ?> ↗
+        </a>
+    </section>
+<?php endif; ?>
+
 </main>
 <?php require_once __DIR__ . '/includes/footer.php'; ?>
 <script src="assets/js/tools.js" defer></script>