feat(ui): increase Live TV grid density

- Categories: 4 → 6 columns on desktop
- Channels: 5 → 8 columns on desktop
- Also bumped tablet values for better density

lib/features/iptv/widgets/live_tv_tab.dart

@@ -261,8 +261,8 @@ class _LiveTVTabState extends ConsumerState<LiveTVTab>
     final columns = ResponsiveLayout.value(
       context,
       mobile: 2,
-      tablet: 3,
-      desktop: 4,
+      tablet: 4,
+      desktop: 6,
     );
 
     return GridView.builder(
@@ -353,8 +353,8 @@ class _LiveTVTabState extends ConsumerState<LiveTVTab>
     final columns = ResponsiveLayout.value(
       context,
       mobile: 2,
-      tablet: 4,
-      desktop: 5,
+      tablet: 5,
+      desktop: 8,
     );
 
     return GridView.builder(