Update README and localization files to enhance project description, add error messages, and improve Persian translations.

app/middleware/demo.ts

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+/**
+ * Demo Route Middleware
+ * 
+ * This is a non-global route middleware example that demonstrates
+ * Nuxt's middleware system without affecting actual navigation.
+ * 
+ * To use this middleware on a specific page, add:
+ * definePageMeta({ middleware: 'demo' })
+ * 
+ * For global middleware, create a file with .global.ts extension.
+ * 
+ * Learn more: https://nuxt.com/docs/guide/directory-structure/middleware
+ */
+
+export default defineNuxtRouteMiddleware((to, from) => {
+  // Example: Log navigation (no-op for demo purposes)
+  if (import.meta.dev) {
+    console.log('[Demo Middleware] Navigating from:', from.path, 'to:', to.path)
+  }
+  
+  // Example: Conditional redirect (commented out to avoid side effects)
+  // if (to.path === '/restricted') {
+  //   return navigateTo('/')
+  // }
+  
+  // Allow navigation to continue
+})