fix(frontend): make Escape dismiss overlays before clearing selection

Escape now peels one layer at a time on the files page: an open tag
editor, pool picker, or delete confirm closes first, and only a second
Escape drops the multi-select. Selection-exit handling moves out of
SelectionBar into a single window handler on the page so precedence is
deterministic rather than dependent on window-listener fire order.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/routes/files/+page.svelte

@@ -27,6 +27,18 @@
 	// ---- Bulk tag editor ----
 	let tagEditorOpen = $state(false);
 
+	// Escape dismisses one layer at a time: an open overlay (tag editor / pool
+	// picker / delete confirm) first, then the selection. The file viewer owns
+	// its own Escape, so we bail out while it's up.
+	function handleEscape(e: KeyboardEvent) {
+		if (e.key !== 'Escape') return;
+		if (tagEditorOpen) tagEditorOpen = false;
+		else if (poolPickerOpen) poolPickerOpen = false;
+		else if (confirmDeleteFiles) confirmDeleteFiles = false;
+		else if (activeFileId) return;
+		else if ($selectionActive) selectionStore.exit();
+	}
+
 	// ---- Add to pool picker ----
 	let poolPickerOpen = $state(false);
 	let pools = $state<Pool[]>([]);
@@ -455,6 +467,8 @@
 	});
 </script>
 
+<svelte:window onkeydown={handleEscape} />
+
 <svelte:head>
 	<title>Files | Tanabata</title>
 </svelte:head>