Add Blancco erasure reports Samba share and webapp viewer

- Samba share at \\server\blancco-reports for automatic report collection
- Webapp reports page with list, download, and delete
- Compliance warning on delete confirmation
- Sidebar link under Tools section

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

webapp/templates/base.html

@@ -149,6 +149,12 @@
           <i class="bi bi-archive"></i> Clonezilla Backups
         </a>
       </li>
+      <li class="nav-item">
+        <a class="nav-link {% if request.endpoint == 'blancco_reports' %}active{% endif %}"
+           href="{{ url_for('blancco_reports') }}">
+          <i class="bi bi-shield-check"></i> Blancco Reports
+        </a>
+      </li>
     </ul>
 
     <div class="nav-section-divider"></div>