fix(ui): bottom-sheet tap-outside only fires while the sheet is shown

The planet/ship-group sheets stay mounted on desktop but are hidden by a
media query (`display: none`); the document-level tap-outside listener
fired regardless, so the first click after selecting a planet cleared the
selection — breaking every desktop inspector/select flow in CI. Guard the
handler on the sheet's computed display (`offsetParent` is unreliable for
`position: fixed`). The swipe handle is naturally inert when hidden.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ui/frontend/src/lib/ui/sheet-dismiss.ts

@@ -25,7 +25,18 @@ export function sheetDismiss(
 	let opts = options;
 	const handle = node.querySelector<HTMLElement>("[data-sheet-handle]") ?? node;
 
+	// The sheet stays mounted on desktop but is hidden by a media query
+	// (`display: none`); the document-level tap-outside listener fires
+	// regardless of that, so it must no-op while the sheet is not shown,
+	// or any click would dismiss the current selection. `offsetParent` is
+	// unreliable here (it is null for `position: fixed`), so check the
+	// computed display directly.
+	function isHidden(): boolean {
+		return getComputedStyle(node).display === "none";
+	}
+
 	function onDocumentPointerDown(event: PointerEvent): void {
+		if (isHidden()) return;
 		const target = event.target;
 		if (target instanceof Node && node.contains(target)) return;
 		opts.onDismiss();