Implement authentication phase with Cidaas OAuth2 integration

- Add authentication middleware to protect routes
- Create API endpoints for login, logout, registration, and user info
- Develop UI components for login and registration forms
- Integrate VeeValidate for form validation
- Update environment configuration for Cidaas settings
- Add i18n support for English and German languages
- Enhance Tailwind CSS for improved styling of auth components
- Document authentication flow and testing procedures

app/components/ui/tabs/Tabs.vue

@@ -0,0 +1,17 @@
+<script setup lang="ts">
+import type { TabsRootProps } from 'reka-ui'
+import { TabsRoot, useForwardPropsEmits } from 'reka-ui'
+
+const props = defineProps<TabsRootProps>()
+const emits = defineEmits<{
+  'update:modelValue': [value: string]
+}>()
+
+const forwarded = useForwardPropsEmits(props, emits)
+</script>
+
+<template>
+  <TabsRoot v-bind="forwarded">
+    <slot />
+  </TabsRoot>
+</template>