fix: Lift menu state to App.vue and translate menu labels to Romanian

- Move menuOpen state from DashboardHeader to App.vue for proper state management
- Pass menuOpen as prop to DashboardHeader component
- Translate hamburger menu labels to Romanian (Navigation, Invoices, Bank & Cash, System, Cache Statistics)

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

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

reports-app/frontend/src/App.vue

@@ -3,6 +3,7 @@
     <!-- New Navigation System -->
     <DashboardHeader
       v-if="authStore.isAuthenticated"
+      :menu-open="menuOpen"
       @menu-toggle="handleMenuToggle"
       @company-changed="handleCompanyChanged"
     />