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/lib/api/auth/authOptions.ts

@@ -15,10 +15,10 @@ const {
     NEXTAUTH_SECRET,
 } = process.env;
 
-// if (!KEYCLOAK_CLIENT_ID) throw new Error("Missing KEYCLOAK_CLIENT_ID");
-// if (!KEYCLOAK_CLIENT_SECRET) throw new Error("Missing KEYCLOAK_CLIENT_SECRET");
-// if (!KEYCLOAK_ISSUER) throw new Error("Missing KEYCLOAK_ISSUER");
-// if (!NEXTAUTH_SECRET) throw new Error("Missing NEXTAUTH_SECRET");
+if (!KEYCLOAK_CLIENT_ID) throw new Error("Missing KEYCLOAK_CLIENT_ID");
+if (!KEYCLOAK_CLIENT_SECRET) throw new Error("Missing KEYCLOAK_CLIENT_SECRET");
+if (!KEYCLOAK_ISSUER) throw new Error("Missing KEYCLOAK_ISSUER");
+if (!NEXTAUTH_SECRET) throw new Error("Missing NEXTAUTH_SECRET");
 
 console.log("[auth] Using Keycloak provider:");
 console.log("  - Client ID:", KEYCLOAK_CLIENT_ID);
@@ -42,8 +42,8 @@ async function isTokenValid(token: string): Promise<boolean> {
 export const authOptions: NextAuthOptions = {
     providers: [
         KeycloakProvider({
-            clientId: KEYCLOAK_CLIENT_ID as string,
-            clientSecret: KEYCLOAK_CLIENT_SECRET as string,
+            clientId: KEYCLOAK_CLIENT_ID,
+            clientSecret: KEYCLOAK_CLIENT_SECRET,
             issuer: KEYCLOAK_ISSUER,
         }),
     ],

internal_frontend/lib/api/serverCall.ts

@@ -1,6 +1,6 @@
 // lib/callBackendApi.ts
 import {getServerSession} from "next-auth";
-import {authOptions} from "@/lib/auth/authOptions";
+import {authOptions} from "@/lib/api/auth/authOptions";
 
 export async function serverCall(
     path: string,

internal_frontend/lib/navigation/breadcrumb-map.ts

@@ -1,20 +1,19 @@
-// lib/breadcrumb-map.ts
+import {customerRoutes} from "@/app/api/customers/customerRoutes";
+
 export const breadcrumbMap: Record<string, string> = {
     'dashboard': 'Dashboard',
     'settings': 'Settings',
     'demo': 'Demo',
     'users': 'User Management',
     'customers': 'Kundenübersicht',
-    // Add more mappings as needed
 };
 
 export const breadcrumbResolvers: Record<string, (id: string) => Promise<string>> = {
     "customers": async (id: string) => {
-        const res = await fetch(`/api/customers/${id}`, {cache: "no-store"});
-        const customer = await res  .json();
+        const res = await fetch(`/api${customerRoutes.getById(id)}`, {cache: "no-store"});
+        const customer = await res.json();
         if (customer.companyName) return `Firma: ${customer.companyName}`;
         if (customer.name) return `Name: ${customer.name}`;
         return `ID: ${id}`;
     },
-    // Add more mappings as needed
 };

internal_frontend/lib/navigation/sidebar-items.ts

@@ -0,0 +1,38 @@
+import {AppWindowIcon, Home, LayoutDashboard} from "lucide-react";
+import {MenuItem, SubMenuItem} from "@/types/navigation/sidebar";
+
+export const rheinItems: MenuItem[] = [
+    {
+        title: "Dashboard",
+        url: "/",
+        icon: Home,
+    },
+    {
+        title: "Apps",
+        url: "/apps",
+        icon: AppWindowIcon,
+    },
+];
+
+export const customerItems: MenuItem[] = [
+    {
+        title: "Kundenübersicht",
+        url: "/customers",
+        icon: LayoutDashboard,
+    },
+];
+
+export const kanzleiItems: SubMenuItem[] = [
+    {
+        title: "Steuer",
+        url: "/demo/kanzlei/steuer",
+    },
+    {
+        title: "Rechtsanwalt",
+        url: "/demo/kanzlei/rechtsanwalt",
+    },
+    {
+        title: "Bilanzbuchhalter",
+        url: "/demo/kanzlei/bilanzbuchhalter",
+    },
+];

internal_frontend/lib/navigation/user-menu-items.ts

@@ -0,0 +1,20 @@
+import {LogOut, Settings} from "lucide-react";
+
+export interface UserMenuItem {
+    title: string;
+    url: string;
+    icon?: typeof Settings;
+}
+
+export const userMenuItems: UserMenuItem[] = [
+    {
+        title: "Settings",
+        url: "/settings",
+        icon: Settings,
+    },
+    {
+        title: "Ausloggen",
+        url: "/api/auth/signout",
+        icon: LogOut,
+    },
+];