feat: support for url based icons (#840)

Co-authored-by: Elias Schneider <login@eliasschneider.com>

frontend/src/lib/components/form/url-file-input.svelte

@@ -0,0 +1,85 @@
+<script lang="ts">
+	import FileInput from '$lib/components/form/file-input.svelte';
+	import FormattedMessage from '$lib/components/formatted-message.svelte';
+	import { Button, buttonVariants } from '$lib/components/ui/button';
+	import { Input } from '$lib/components/ui/input';
+	import { Label } from '$lib/components/ui/label';
+	import * as Popover from '$lib/components/ui/popover';
+	import { m } from '$lib/paraglide/messages';
+	import { cn } from '$lib/utils/style';
+	import { LucideChevronDown } from '@lucide/svelte';
+
+	let {
+		label,
+		accept,
+		onchange
+	}: {
+		label: string;
+		accept?: string;
+		onchange: (file: File | string | null) => void;
+	} = $props();
+
+	let url = $state('');
+	let hasError = $state(false);
+
+	async function handleFileChange(e: Event) {
+		const file = (e.target as HTMLInputElement).files?.[0] || null;
+		url = '';
+		hasError = false;
+		onchange(file);
+	}
+
+	async function handleUrlChange(e: Event) {
+		const url = (e.target as HTMLInputElement).value.trim();
+		if (!url) return;
+
+		try {
+			new URL(url);
+			hasError = false;
+		} catch {
+			hasError = true;
+			return;
+		}
+
+		onchange(url);
+	}
+</script>
+
+<div class="flex">
+	<FileInput
+		id="logo"
+		variant="secondary"
+		{accept}
+		onchange={handleFileChange}
+		onclick={(e: any) => (e.target.value = '')}
+	>
+		<Button variant="secondary" class="rounded-r-none">
+			{label}
+		</Button>
+	</FileInput>
+	<Popover.Root>
+		<Popover.Trigger
+			class={cn(buttonVariants({ variant: 'secondary' }), 'rounded-l-none border-l')}
+		>
+			<LucideChevronDown class="size-4" /></Popover.Trigger
+		>
+		<Popover.Content class="w-80">
+			<Label for="file-url" class="text-xs">URL</Label>
+			<Input
+				id="file-url"
+				placeholder=""
+				value={url}
+				oninput={(e) => (url = e.currentTarget.value)}
+				onfocusout={handleUrlChange}
+				aria-invalid={hasError}
+			/>
+			{#if hasError}
+				<p class="text-destructive mt-1 text-start text-xs">{m.invalid_url()}</p>
+			{/if}
+
+			<p class="text-muted-foreground mt-2 text-xs">
+				<FormattedMessage m={m.logo_from_url_description()} />
+			</p>
+		</Popover.Content>
+	</Popover.Root>
+</div>