pwa / offline mode

- @vite-pwa/sveltekit: workbox precache (incl. pdfjs worker), generated manifest, prompt-style updates via PwaUpdatePrompt toast
- prerendered routes for offline navigation, PWA icons, theme-color + apple-touch-icon
- pwa offline/update e2e suite (pnpm test:pwa, playwright.pwa.config.ts)
- datenschutz: offline/install section; prettier cleanup of shadcn components

src/lib/components/ui/card/card-action.svelte

@@ -1,6 +1,6 @@
 <script lang="ts">
-	import { cn, type WithElementRef } from "$lib/utils.js";
-	import type { HTMLAttributes } from "svelte/elements";
+	import { cn, type WithElementRef } from '$lib/utils.js';
+	import type { HTMLAttributes } from 'svelte/elements';
 
 	let {
 		ref = $bindable(null),
@@ -14,7 +14,7 @@
 	bind:this={ref}
 	data-slot="card-action"
 	class={cn(
-		"cn-card-action col-start-2 row-span-2 row-start-1 self-start justify-self-end",
+		'cn-card-action col-start-2 row-span-2 row-start-1 self-start justify-self-end',
 		className
 	)}
 	{...restProps}