feat: implement sidebar components and authentication flow

- Added sidebar menu components including sidebar-menu-item, sidebar-menu-skeleton, sidebar-menu-sub-button, sidebar-menu-sub-item, sidebar-menu-sub, sidebar-menu, sidebar-provider, sidebar-rail, sidebar-separator, sidebar-trigger, and sidebar.
- Introduced skeleton loading states for sidebar items.
- Integrated tooltip components for enhanced user interaction.
- Developed mobile responsiveness using media queries.
- Established authentication flow with Keycloak, including login, logout, and token management.
- Implemented server-side redirection based on authentication status.
- Enhanced error handling and logging for authentication processes.

frontend/src/lib/components/ui/dropdown-menu/dropdown-menu-trigger.svelte

@@ -0,0 +1,7 @@
+<script lang="ts">
+	import { DropdownMenu as DropdownMenuPrimitive } from "bits-ui";
+
+	let { ref = $bindable(null), ...restProps }: DropdownMenuPrimitive.TriggerProps = $props();
+</script>
+
+<DropdownMenuPrimitive.Trigger bind:ref data-slot="dropdown-menu-trigger" {...restProps} />