chore: stage all in-progress work before repo split

Web app: new entities (Image, RenderedAsset, SharedImage, Token,
DeviceImageHistory), enums, repositories, controllers, message handlers,
migrations, tests, frontend upload/library/sticker UI, Vue components.

Firmware: EPD background screen binaries + gen scripts, setup_bg header.

Infra: ddev config, test bundle, gitignore coverage dir.

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

frontend/src/main.ts

@@ -1,5 +1,6 @@
 import { createApp } from 'vue'
 import { createPinia } from 'pinia'
+import VueKonva from 'vue-konva'
 import '@/styles/global.scss'
 import App from './App.vue'
 import router from '@/router'
@@ -7,4 +8,5 @@ import router from '@/router'
 const app = createApp(App)
 app.use(createPinia())
 app.use(router)
+app.use(VueKonva)
 app.mount('#app')