feat: orientation model, password confirm, frontend build

- Collapse orientation to landscape/portrait (ribbon left = portrait standard)
- Add OrientationPicker component and wire settings sheet in HomeView
- Add password confirmation field to registration form (RepeatedType)
- Build frontend SPA to public/build/

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

templates/setup/configure.html.twig

@@ -47,8 +47,8 @@
         <div class="field">
             <label for="orientation">Display orientation</label>
             <select id="orientation" name="orientation">
-                <option value="landscape" {% if device.orientation.value == 'landscape' %}selected{% endif %}>Landscape</option>
-                <option value="portrait"  {% if device.orientation.value == 'portrait'  %}selected{% endif %}>Portrait</option>
+                <option value="landscape" {% if device.orientation.value == 'landscape' %}selected{% endif %}>Landscape — ribbon at bottom</option>
+                <option value="portrait"  {% if device.orientation.value == 'portrait'  %}selected{% endif %}>Portrait — ribbon on left</option>
             </select>
         </div>