configurable default homepage

src/lib/utils/landing.ts

@@ -0,0 +1,21 @@
+// Custom-homepage landing decision (pure). SSR is off, so `/`'s client-side load (+page.ts)
+// decides whether opening the app should redirect to the user's landing page. Kept pure so the
+// redirect rule lives in one testable place.
+
+export interface NavEffective {
+	landingPage?: string | null;
+	envClickPage?: string | null;
+}
+
+/**
+ * Where to send the user when opening `/`, or null to stay on the dashboard. Redirects
+ * whenever the landing page is a real page other than the dashboard, UNLESS the URL carries the
+ * `?home` marker (the sidebar's Dashboard link sets it, so clicking Dashboard is not bounced
+ * away). The environment is not forced here - it stays whatever the store already holds.
+ */
+export function landingRedirectTarget(nav: NavEffective | null | undefined, hasHomeMarker: boolean): string | null {
+	if (hasHomeMarker) return null;
+	const page = nav?.landingPage;
+	if (!page || page === 'dashboard') return null;
+	return `/${page}`;
+}