Restore rounded-rectangle shape for the Check Grammar button.

The pill-style Capsule clip was making the button sides fully oval; use AppTheme.buttonCornerRadius instead.

Co-authored-by: Cursor <cursoragent@cursor.com>

gramora/Views/Components/GradientButton.swift

@@ -22,7 +22,7 @@ struct GradientButton: View {
             .padding(.vertical, 15)
             .frame(maxWidth: .infinity)
             .background(AppTheme.primaryGradient)
-            .clipShape(Capsule())
+            .clipShape(RoundedRectangle(cornerRadius: AppTheme.buttonCornerRadius))
             .shadow(color: AppTheme.teal.opacity(0.30), radius: 10, y: 4)
         }
         .buttonStyle(.plain)