Centralize authentication logic and integrate token refresh mechanism

- Introduce `AuthWrapper` component for streamlined session-based layouts and authentication handling.
- Add new utilities (`tokenUtils.ts`) for JWT decoding, token expiration checks, and refresh operations via Keycloak.
- Refactor `serverCall` and `authOptions` to use centralized token refresh logic, removing redundant implementations.
- Implement `ClientSessionProvider` for consistent session management across the client application.
- Simplify `RootLayout` by delegating authentication enforcement to `AuthWrapper`.

internal_frontend/components/ClientSessionProvider.tsx

@@ -0,0 +1,12 @@
+"use client";
+
+import {SessionProvider} from "next-auth/react";
+import React from "react";
+
+interface Props {
+    children: React.ReactNode;
+}
+
+export function ClientSessionProvider({children}: Props) {
+    return <SessionProvider refetchInterval={180}>{children}</SessionProvider>;
+}

internal_frontend/components/auth-wrapper.tsx

@@ -0,0 +1,63 @@
+"use client";
+
+import React from "react";
+import {useSession} from "next-auth/react";
+import {SidebarInset, SidebarProvider, SidebarTrigger} from "@/components/ui/sidebar";
+import {AppSidebar} from "@/components/app-sidebar";
+import {Separator} from "@/components/ui/separator";
+import {DynamicBreadcrumb} from "@/components/dynamic-breadcrumb";
+import LoginScreen from "@/components/login-screen";
+import {ErrorBoundary} from "@/components/error-boundary";
+
+interface AuthWrapperProps {
+    children: React.ReactNode;
+}
+
+export function AuthWrapper({children}: AuthWrapperProps) {
+    const {data: session, status} = useSession();
+
+    if (status === "loading") {
+        return (
+            <div className="flex items-center justify-center min-h-screen">
+                <div className="animate-spin rounded-full h-32 w-32 border-b-2 border-gray-900"></div>
+            </div>
+        );
+    }
+
+    if (session?.accessToken) {
+        return (
+            <SidebarProvider
+                style={
+                    {
+                        "--sidebar-width": "calc(var(--spacing) * 72)",
+                        "--header-height": "calc(var(--spacing) * 12)",
+                    } as React.CSSProperties
+                }
+            >
+                <AppSidebar/>
+                <SidebarInset>
+                    <header
+                        className="flex h-16 shrink-0 items-center gap-2 transition-[width,height] ease-linear group-has-data-[collapsible=icon]/sidebar-wrapper:h-12">
+                        <div className="flex items-center gap-2 px-4">
+                            <SidebarTrigger className="-ml-1"/>
+                            <Separator
+                                orientation="vertical"
+                                className="mr-2 data-[orientation=vertical]:h-4"
+                            />
+                            <DynamicBreadcrumb/>
+                        </div>
+                    </header>
+                    <ErrorBoundary>
+                        {children}
+                    </ErrorBoundary>
+                </SidebarInset>
+            </SidebarProvider>
+        );
+    }
+
+    return (
+        <ErrorBoundary>
+            <LoginScreen/>
+        </ErrorBoundary>
+    );
+}