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/alert/Alert.vue

@@ -0,0 +1,21 @@
+<script setup lang="ts">
+import type { HTMLAttributes } from 'vue'
+import type { AlertVariants } from '.'
+import { cn } from '~/lib/utils'
+import { alertVariants } from '.'
+
+interface Props {
+  variant?: AlertVariants['variant']
+  class?: HTMLAttributes['class']
+}
+
+const props = withDefaults(defineProps<Props>(), {
+  variant: 'default',
+})
+</script>
+
+<template>
+  <div :class="cn(alertVariants({ variant }), props.class)" role="alert">
+    <slot />
+  </div>
+</template>

app/components/ui/alert/AlertDescription.vue

@@ -0,0 +1,16 @@
+<script setup lang="ts">
+import type { HTMLAttributes } from 'vue'
+import { cn } from '~/lib/utils'
+
+interface Props {
+  class?: HTMLAttributes['class']
+}
+
+const props = defineProps<Props>()
+</script>
+
+<template>
+  <div :class="cn('text-sm [&_p]:leading-relaxed', props.class)">
+    <slot />
+  </div>
+</template>

app/components/ui/alert/AlertTitle.vue

@@ -0,0 +1,16 @@
+<script setup lang="ts">
+import type { HTMLAttributes } from 'vue'
+import { cn } from '~/lib/utils'
+
+interface Props {
+  class?: HTMLAttributes['class']
+}
+
+const props = defineProps<Props>()
+</script>
+
+<template>
+  <h5 :class="cn('mb-1 font-medium leading-none tracking-tight', props.class)">
+    <slot />
+  </h5>
+</template>

app/components/ui/alert/index.ts

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+import type { VariantProps } from 'class-variance-authority'
+import { cva } from 'class-variance-authority'
+
+export { default as Alert } from './Alert.vue'
+export { default as AlertDescription } from './AlertDescription.vue'
+export { default as AlertTitle } from './AlertTitle.vue'
+
+export const alertVariants = cva(
+  'relative w-full rounded-lg border p-4 [&>svg~*]:pl-7 [&>svg+div]:translate-y-[-3px] [&>svg]:absolute [&>svg]:left-4 [&>svg]:top-4 [&>svg]:text-foreground',
+  {
+    variants: {
+      variant: {
+        default: 'bg-background text-foreground',
+        destructive:
+          'border-destructive/50 text-destructive dark:border-destructive [&>svg]:text-destructive',
+      },
+    },
+    defaultVariants: {
+      variant: 'default',
+    },
+  }
+)
+
+export type AlertVariants = VariantProps<typeof alertVariants>