Refactor navigation structure and API routes

- Centralize user menu, sidebar items, and breadcrumb logic.
- Map consistent API endpoints in `customerRoutes`.
- Replace inline route definitions with reusable constants.
- Refactor auth configuration file location.
- Improve `<Link>` usage to replace static `<a>` elements.
- Adjust sidebar and dropdown components to use dynamic navigation configurations.

internal_frontend/components/dynamic-breadcrumb.tsx

@@ -11,8 +11,8 @@ import {
 } from '@/components/ui/breadcrumb';
 import {Skeleton} from "@/components/ui/skeleton";
 import React, {useEffect, useState} from 'react';
-import {getBreadcrumbs} from '@/utils/BreadcrumbUtils';
-import {breadcrumbResolvers} from "@/lib/breadcrumb-map";
+import {getBreadcrumbs} from '@/services/navigation/breadcrumb-utils';
+import {breadcrumbResolvers} from "@/lib/navigation/breadcrumb-map";
 
 interface ResolvedBreadcrumb {
     href: string;