výkon: manualChunks vendor knihoven a lazy route komponenty

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/vite.config.ts

@@ -24,6 +24,17 @@ export default defineConfig(async () => {
       outDir: 'dist',
       assetsDir: 'assets',
       chunkSizeWarningLimit: 750,
+      rollupOptions: {
+        output: {
+          // Stabilní vendor chunky: react jádro, grafové knihovny zvlášť (cache + menší initial load).
+          manualChunks: {
+            'vendor-react': ['react', 'react-dom', 'react-router-dom'],
+            'vendor-recharts': ['recharts'],
+            'vendor-nivo': ['@nivo/core', '@nivo/sankey'],
+            'vendor-chartjs': ['chart.js'],
+          },
+        },
+      },
     },
     server: {
       proxy: {