fix: Resolve shared component styling and Vite module deduplication

- Add dedupe option for vue, vue-router, pinia, primevue in both Vite configs
  to prevent duplicate module issues when using shared components
- Add optimizeDeps and commonjsOptions for better shared module handling
- Fix CompanySelector and PeriodSelector header variants to support both
  light headers (using CSS variables) and gradient headers (white text)
- Make hamburger button always display:flex for consistent mobile layout

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

reports-app/frontend/vite.config.js

@@ -20,7 +20,8 @@ export default defineConfig({
     alias: {
       '@': fileURLToPath(new URL('./src', import.meta.url)),
       '@shared': fileURLToPath(new URL('../../shared', import.meta.url))
-    }
+    },
+    dedupe: ['vue', 'vue-router', 'pinia', 'primevue']
   },
   server: {
     port: 3000,
@@ -52,9 +53,15 @@ export default defineConfig({
       }
     }
   },
+  optimizeDeps: {
+    include: ['vue', 'vue-router', 'pinia']
+  },
   build: {
     outDir: 'dist',
     sourcemap: true,
+    commonjsOptions: {
+      include: [/node_modules/, /shared/]
+    },
     // Cache busting - generează hash-uri noi la fiecare build
     assetsInlineLimit: 0, // Nu inline asset-uri mici, folosește fișiere separate cu hash
     rollupOptions: {