fix layout issues

src/theme/adaptive.ts

@@ -0,0 +1,11 @@
+/** Minimum width for two-pane layouts — below this, panes get too cramped to use. */
+export const WIDE_MIN_WIDTH = 600;
+
+/**
+ * True when a window should use a two-pane / wide layout: wide enough for two
+ * useful panes and wider than it is tall (single columns overflow short windows).
+ * Pass inset-adjusted dimensions (window minus safe areas).
+ */
+export function isWideWindow(availableWidth: number, availableHeight: number): boolean {
+  return availableWidth >= WIDE_MIN_WIDTH && availableWidth > availableHeight;
+}