fix(templates): ensure template use frontend css

this fix the nextcloud login + drive selector (chroot)
    fix also invitation / magic link

    also correct the UX: once user has logged in nextcloud, show an explicita page

frontend/package.json

@@ -9,6 +9,7 @@
   "scripts": {
     "dev": "vite dev",
     "build": "vite build",
+    "postbuild": "node scripts/emit-askama-common.mjs",
     "preview": "vite preview",
     "check": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json && eslint . && stylelint \"src/**/*.{css,svelte}\" && prettier --check .",
     "check:watch": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json --watch",