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>

frontend/src/stores/devices.ts

@@ -21,5 +21,18 @@ export const useDevicesStore = defineStore('devices', () => {
     }
   }
 
-  return { devices, loading, error, fetchDevices }
+  async function updateDevice(id: number, patch: Partial<Pick<Device, 'name' | 'orientation' | 'rotationIntervalHours' | 'uniquenessWindow'>>) {
+    const res = await fetch(`/api/devices/${id}`, {
+      method: 'PATCH',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify(patch),
+    })
+    if (!res.ok) throw new Error('Failed to update device')
+    const updated: Device = await res.json()
+    const idx = devices.value.findIndex(d => d.id === id)
+    if (idx !== -1) devices.value[idx] = updated
+    return updated
+  }
+
+  return { devices, loading, error, fetchDevices, updateDevice }
 })