feat(i18n): enhance locale support and add under-construction messages

- Updated Header.tsx to use current locale in navigation links for proper routing
- Increased MiniSparkline chart dimensions in market-stats.tsx for better visibility
- Added under-construction translations for market, about, and prices pages in en.json and pt.json
- Minor formatting adjustments with added blank lines across multiple components

These changes improve internationalization and user experience by ensuring locale-aware navigation and providing informative placeholders for upcoming features.

components/sections/market-stats.tsx

@@ -35,13 +35,13 @@ function MiniSparkline({ data, color }: { data: number[]; color: string }) {
   }));
 
   return (
-    <div className="h-8 w-full min-h-[32px] min-w-[120px]">
+    <div className="h-12 w-full min-h-[48px] min-w-[150px]">
       <ResponsiveContainer width="100%" height="100%">
-        <AreaChart 
-          data={chartData} 
+        <AreaChart
+          data={chartData}
           margin={{ top: 2, right: 2, left: 2, bottom: 2 }}
-          width={120}
-          height={32}
+          width={150}
+          height={48}
         >
           <defs>
             <linearGradient