Implement Password Grant Flow for Authentication and Enhance User Experience

- Introduced Password Grant Flow for user authentication, allowing direct login with email and password.
- Updated `useAuth` composable to manage login and logout processes, including Single Sign-Out from Cidaas.
- Enhanced user interface with a new `UserMenu` component displaying user information and logout functionality.
- Updated homepage to show personalized greetings for logged-in users and a login prompt for guests.
- Added logout confirmation page with a countdown redirect to the homepage.
- Documented the implementation details and future enhancements for OAuth2 flows in CLAUDE.md and other relevant documentation.
- Added test credentials and guidelines for automated testing in the new TESTING.md file.

app/components/ui/avatar/Avatar.vue

@@ -0,0 +1,22 @@
+<script setup lang="ts">
+import type { HTMLAttributes } from "vue"
+import type { AvatarVariants } from "."
+import { AvatarRoot } from "reka-ui"
+import { cn } from '~/lib/utils'
+import { avatarVariant } from "."
+
+const props = withDefaults(defineProps<{
+  class?: HTMLAttributes["class"]
+  size?: AvatarVariants["size"]
+  shape?: AvatarVariants["shape"]
+}>(), {
+  size: "sm",
+  shape: "circle",
+})
+</script>
+
+<template>
+  <AvatarRoot :class="cn(avatarVariant({ size, shape }), props.class)">
+    <slot />
+  </AvatarRoot>
+</template>

app/components/ui/avatar/AvatarFallback.vue

@@ -0,0 +1,12 @@
+<script setup lang="ts">
+import type { AvatarFallbackProps } from "reka-ui"
+import { AvatarFallback } from "reka-ui"
+
+const props = defineProps<AvatarFallbackProps>()
+</script>
+
+<template>
+  <AvatarFallback v-bind="props">
+    <slot />
+  </AvatarFallback>
+</template>

app/components/ui/avatar/AvatarImage.vue

@@ -0,0 +1,12 @@
+<script setup lang="ts">
+import type { AvatarImageProps } from "reka-ui"
+import { AvatarImage } from "reka-ui"
+
+const props = defineProps<AvatarImageProps>()
+</script>
+
+<template>
+  <AvatarImage v-bind="props" class="h-full w-full object-cover">
+    <slot />
+  </AvatarImage>
+</template>

app/components/ui/avatar/index.ts

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+import type { VariantProps } from "class-variance-authority"
+import { cva } from "class-variance-authority"
+
+export { default as Avatar } from "./Avatar.vue"
+export { default as AvatarFallback } from "./AvatarFallback.vue"
+export { default as AvatarImage } from "./AvatarImage.vue"
+
+export const avatarVariant = cva(
+  "inline-flex items-center justify-center font-normal text-foreground select-none shrink-0 bg-secondary overflow-hidden",
+  {
+    variants: {
+      size: {
+        sm: "h-10 w-10 text-xs",
+        base: "h-16 w-16 text-2xl",
+        lg: "h-32 w-32 text-5xl",
+      },
+      shape: {
+        circle: "rounded-full",
+        square: "rounded-md",
+      },
+    },
+  },
+)
+
+export type AvatarVariants = VariantProps<typeof avatarVariant>