Fix tvOS memory crash: cap highlights to 50, replace blurs with gradients

The app was crashing from memory pressure on tvOS. Three causes fixed:

1. Feed was rendering all 418 highlights at once — capped to 50 items.

2. FeaturedGameCard had 3 blur effects (radius 80-120) on large circles
   for team color glow — replaced with a single LinearGradient. Same
   visual effect, fraction of the GPU memory.

3. BroadcastBackground had 3 blurred circles (radius 120-140, 680-900px)
   rendering on every screen — replaced with RadialGradients which are
   composited by the GPU natively without offscreen render passes.

Also fixed iOS build: replaced tvOS-only font refs (tvSectionTitle,
tvBody) with cross-platform equivalents in DashboardView fallback state.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

mlbTVOS/Views/Components/DataPanel.swift

@@ -32,9 +32,9 @@ struct DataPanel<Content: View>: View {
             if let code = teamAccentCode {
                 RoundedRectangle(cornerRadius: 1.5)
                     .fill(TeamAssets.color(for: code))
-                    .frame(width: 3)
-                    .padding(.vertical, 6)
-                    .padding(.leading, 4)
+                    .frame(width: 4)
+                    .padding(.vertical, 8)
+                    .padding(.leading, 6)
             }
 
             VStack(alignment: .leading, spacing: 0) {
@@ -43,15 +43,24 @@ struct DataPanel<Content: View>: View {
             .frame(maxWidth: .infinity, alignment: .leading)
             .padding(density.padding)
         }
-        .background(
-            RoundedRectangle(cornerRadius: density.cornerRadius)
-                .fill(DS.Colors.panelFill)
+        .background {
+            RoundedRectangle(cornerRadius: density.cornerRadius, style: .continuous)
+                .fill(
+                    LinearGradient(
+                        colors: [
+                            DS.Colors.panelFill,
+                            DS.Colors.panelFillMuted,
+                        ],
+                        startPoint: .topLeading,
+                        endPoint: .bottomTrailing
+                    )
+                )
+                .overlay {
+                    RoundedRectangle(cornerRadius: density.cornerRadius, style: .continuous)
+                        .strokeBorder(DS.Colors.panelStroke, lineWidth: 1)
+                }
                 .shadow(color: DS.Shadows.card, radius: DS.Shadows.cardRadius, y: DS.Shadows.cardY)
-        )
-        .overlay(
-            RoundedRectangle(cornerRadius: density.cornerRadius)
-                .strokeBorder(DS.Colors.panelStroke, lineWidth: 0.5)
-        )
+        }
     }
 }