fix: sidebar opened by default on desktop

src/components/Sidebar.tsx

@@ -24,21 +24,21 @@ function useIsWide(): boolean {
 /* -----------------------------
    Shared sidebar logic
 ------------------------------*/
-function useSidebarState() {
+function useSidebarState(panels: SidebarPanel[], isWide: boolean) {
   const [activeId, setActiveId] = useState<string | null>(null);
 
+  // open first panel by default ONLY on first mount (desktop only)
+  const [initialized, setInitialized] = useState(false);
+
+  if (!initialized && isWide) {
+    setActiveId(panels[0]?.id ?? null);
+    setInitialized(true);
+  }
+
   const setClosed = () => setActiveId(null);
 
-  const toggle = (id: string, effectiveId: string | null) => {
-    setActiveId((prev) =>
-      prev === id || (effectiveId === id && prev === null) ? null : id,
-    );
-  };
-
-  const resolveEffectiveId = (isWide: boolean, panels: SidebarPanel[]) => {
-    return activeId === null
-      ? null
-      : (activeId ?? (isWide ? (panels[0]?.id ?? null) : null));
+  const toggle = (id: string) => {
+    setActiveId((prev) => (prev === id ? null : id));
   };
 
   return {
@@ -46,7 +46,6 @@ function useSidebarState() {
     setActiveId,
     setClosed,
     toggle,
-    resolveEffectiveId,
   };
 }
 
@@ -159,9 +158,9 @@ function IconRail({
 export default function Sidebar({ panels }: { panels: SidebarPanel[] }) {
   const isWide = useIsWide();
 
-  const { setClosed, toggle, resolveEffectiveId } = useSidebarState();
+  const { activeId, setClosed, toggle } = useSidebarState(panels, isWide);
 
-  const effectiveId = resolveEffectiveId(isWide, panels);
+  const effectiveId = activeId;
   const activePanel = panels.find((p) => p.id === effectiveId);
   const isOpen = !!activePanel;