Add Android APK download feature

- Create android/ directory with Kotlin + Jetpack Compose project
- Build APK at public/sysadmin.apk
- Add sidebar nav item and dashboard stat card to download APK
- Add android/ to .gitignore

views/layouts/main.php

@@ -76,6 +76,14 @@
                         </a>
                     </li>
                     <?php endif; ?>
+                    <li class="nav-divider"></li>
+                    <li class="nav-section">Mobile</li>
+                    <li class="nav-item">
+                        <a href="/sysadmin.apk" class="nav-link" download>
+                            <i class="fas fa-download"></i>
+                            <span>Download APK</span>
+                        </a>
+                    </li>
                 </ul>
             </nav>
             <div class="sidebar-footer">