fix: hide vertical nav rail on tablet to avoid duplicate navigation (#40)

Author: wrenix

app/[locale]/calendar/page.tsx

@@ -604,7 +604,7 @@ export default function CalendarPage() {
   return (
     <div className="flex h-screen bg-background">
       {/* Left Navigation Rail */}
-      {!isMobile && (
+      {!isMobile && !isTablet && (
         <div className="w-14 border-r border-border bg-secondary flex flex-col items-center py-3 flex-shrink-0">
           <NavigationRail collapsed className="py-0" />
         </div>

app/[locale]/contacts/page.tsx

@@ -430,7 +430,7 @@ export default function ContactsPage() {
 
   return (
     <div className="flex h-screen bg-background">
-      {!isMobile && (
+      {!isMobile && !isTablet && (
         <div className="w-14 border-r border-border bg-secondary flex flex-col items-center flex-shrink-0">
           <NavigationRail collapsed />
         </div>