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-content.svelte

@@ -1,6 +1,6 @@
 <script lang="ts">
-	import type { HTMLAttributes } from "svelte/elements";
-	import { cn, type WithElementRef } from "$lib/utils.js";
+	import type { HTMLAttributes } from 'svelte/elements';
+	import { cn, type WithElementRef } from '$lib/utils.js';
 
 	let {
 		ref = $bindable(null),
@@ -13,7 +13,7 @@
 <div
 	bind:this={ref}
 	data-slot="card-content"
-	class={cn("px-4 group-data-[size=sm]/card:px-3", className)}
+	class={cn('px-4 group-data-[size=sm]/card:px-3', className)}
 	{...restProps}
 >
 	{@render children?.()}