feat(isac): add game data icon management

src/lib/components/IconUploadField.svelte

@@ -0,0 +1,26 @@
+<script lang="ts">
+	import { onDestroy } from 'svelte';
+	let {
+		currentUrl = '',
+		label = 'ICON'
+	}: { currentUrl?: string | null; label?: string } = $props();
+	let previewUrl = $state('');
+	let fileName = $state('');
+	const choose = (event: Event) => {
+		const file = (event.currentTarget as HTMLInputElement).files?.[0];
+		if (previewUrl) URL.revokeObjectURL(previewUrl);
+		previewUrl = file && file.type !== 'image/svg+xml' ? URL.createObjectURL(file) : '';
+		fileName = file?.name ?? '';
+	};
+	onDestroy(() => { if (previewUrl) URL.revokeObjectURL(previewUrl); });
+</script>
+
+<fieldset class="icon-upload-field">
+	<legend>{label}</legend>
+	<div class="icon-upload-preview">
+		{#if previewUrl || currentUrl}<img src={previewUrl || currentUrl || ''} alt="Current icon preview"/>{:else}<span>NO ICON</span>{/if}
+	</div>
+	<label><input name="icon" type="file" accept="image/svg+xml,image/png,image/webp,image/avif" onchange={choose}/><span>{fileName || (currentUrl ? 'REPLACE ICON' : 'UPLOAD ICON')}</span></label>
+	{#if currentUrl}<label class="icon-remove"><input name="removeIcon" type="checkbox" value="1"/><span>REMOVE CURRENT ICON</span></label>{/if}
+	<small>TRANSPARENT SVG, PNG, WEBP, OR AVIF · 2 MiB MAX</small>
+</fieldset>