Move rune-based state modules into lib/state

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web-player/src/lib/state/toggle.svelte.ts

@@ -0,0 +1,18 @@
+export function createToggle(initial = false) {
+	let open = $state(initial);
+
+	return {
+		get open() {
+			return open;
+		},
+		show() {
+			open = true;
+		},
+		close() {
+			open = false;
+		},
+		toggle() {
+			open = !open;
+		}
+	};
+}