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>

migrations/Version20260504000001.php

@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+final class Version20260504000001 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Collapse portrait_left / portrait_right into a single portrait orientation (ribbon always on left)';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->addSql("UPDATE device SET orientation = 'portrait' WHERE orientation IN ('portrait_left', 'portrait_right')");
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql("UPDATE device SET orientation = 'portrait_left' WHERE orientation = 'portrait'");
+    }
+}