feat(webapp): redesign dashboard with shadcn-style UI shell

WebApp/src/lib/components/ui/avatar/avatar-fallback.svelte

@@ -0,0 +1,20 @@
+<script lang="ts">
+	import { Avatar as AvatarPrimitive } from "bits-ui";
+	import { cn } from "$lib/utils.js";
+
+	let {
+		ref = $bindable(null),
+		class: className,
+		...restProps
+	}: AvatarPrimitive.FallbackProps = $props();
+</script>
+
+<AvatarPrimitive.Fallback
+	bind:ref
+	data-slot="avatar-fallback"
+	class={cn(
+		"bg-muted text-muted-foreground rounded-full flex size-full items-center justify-center text-sm group-data-[size=sm]/avatar:text-xs",
+		className
+	)}
+	{...restProps}
+/>