feat(i18n,drupal): consolidate locale codes and add Drupal infrastructure

i18n changes:
- Remove qpv locale code, standardize on vp-VL for Viossa
- Remove wp-VL duplicate, keep locale structure clean
- Update langcode types in DrupalService from 'qpv' to 'vp-VL'

Drupal integration additions:
- Add PreviewDrupalService for viewing unpublished content
- Add authentication system with Pinia store and composables
- Add meta tag management system (SEO, OpenGraph, Twitter)
- Add route guards for protected admin routes
- Add login/preview/admin pages

Locale file changes:
- Deleted: qpv.ftl (duplicate of vp-VL.ftl)
- Kept: en_US.ftl, es_LA.ftl, vp_VL.ftl, wp_VL.ftl

apps/vdn-static/src/utils/drupal-meta.ts

@@ -0,0 +1,252 @@
+/**
+ * Drupal Content Type Meta Tag Integration
+ * 
+ * This module provides utilities for generating meta tags from Drupal content types
+ * via the JSON:API responses.
+ */
+
+import { computed } from 'vue'
+import { useRoute } from 'vue-router'
+import { useMeta, type MetaConfig } from '../composables/useMeta'
+import type { 
+  ArticleNode, 
+  PageNode, 
+  LearningResourceNode,
+  DrupalNodeAttributes 
+} from '../types/drupal'
+
+/**
+ * Generates meta configuration from a Drupal node
+ * 
+ * @param node - Drupal node from JSON:API response
+ * @param baseUrl - Base URL for canonical links
+ * @returns Meta configuration object
+ */
+export function generateDrupalNodeMeta(
+  node: ArticleNode | PageNode | LearningResourceNode,
+  baseUrl: string = 'https://viossa.net'
+): MetaConfig {
+  const { attributes } = node
+  const path = attributes.path?.alias || `node/${node.id}`
+  
+  const meta: MetaConfig = {
+    title: attributes.title,
+    description: attributes.body?.summary || generateExcerpt(attributes.body?.processed || ''),
+    canonical: `${baseUrl}${path}`,
+    author: 'Viossa Team', // Could be extracted from relationships if available
+    og: {
+      type: 'article',
+      title: attributes.title,
+      description: attributes.body?.summary || generateExcerpt(attributes.body?.processed || ''),
+      url: `${baseUrl}${path}`,
+      image: '/images/og-default.jpg', // Could be extracted from relationships
+    },
+    twitter: {
+      card: 'summary_large_image',
+      title: attributes.title,
+      description: attributes.body?.summary || generateExcerpt(attributes.body?.processed || ''),
+      image: '/images/twitter-default.jpg',
+    },
+    custom: [
+      {
+        property: 'article:published_time',
+        content: attributes.created,
+      },
+      {
+        property: 'article:modified_time',
+        content: attributes.changed,
+      },
+    ],
+  }
+
+  // Add sticky/promote as robots meta
+  if (attributes.sticky || attributes.promote) {
+    meta.custom?.push({
+      name: 'robots',
+      content: 'index, follow',
+    })
+  }
+
+  // Add status-based robots meta
+  if (!attributes.status) {
+    meta.custom?.push({
+      name: 'robots',
+      content: 'noindex, nofollow',
+    })
+  }
+
+  return meta
+}
+
+/**
+ * Generates meta configuration specifically for Article content type
+ * 
+ * @param node - Article node from JSON:API
+ * @param baseUrl - Base URL for canonical links
+ * @returns Meta configuration object
+ */
+export function generateArticleContentMeta(
+  node: ArticleNode,
+  baseUrl: string = 'https://viossa.net'
+): MetaConfig {
+  const baseMeta = generateDrupalNodeMeta(node, baseUrl)
+  
+  return {
+    ...baseMeta,
+    og: {
+      ...baseMeta.og,
+      type: 'article',
+    },
+    custom: [
+      ...(baseMeta.custom || []),
+      // Article-specific meta tags
+      {
+        property: 'article:section',
+        content: 'Language Learning',
+      },
+    ],
+  }
+}
+
+/**
+ * Generates meta configuration specifically for Page content type
+ * 
+ * @param node - Page node from JSON:API
+ * @param baseUrl - Base URL for canonical links
+ * @returns Meta configuration object
+ */
+export function generatePageContentMeta(
+  node: PageNode,
+  baseUrl: string = 'https://viossa.net'
+): MetaConfig {
+  const baseMeta = generateDrupalNodeMeta(node, baseUrl)
+  
+  return {
+    ...baseMeta,
+    og: {
+      ...baseMeta.og,
+      type: 'website',
+    },
+  }
+}
+
+/**
+ * Generates meta configuration specifically for Learning Resource content type
+ * 
+ * @param node - Learning Resource node from JSON:API
+ * @param baseUrl - Base URL for canonical links
+ * @returns Meta configuration object
+ */
+export function generateLearningResourceMeta(
+  node: LearningResourceNode,
+  baseUrl: string = 'https://viossa.net'
+): MetaConfig {
+  const baseMeta = generateDrupalNodeMeta(node, baseUrl)
+  
+  return {
+    ...baseMeta,
+    title: `${baseMeta.title} - Viossa Resources`,
+    og: {
+      ...baseMeta.og,
+      type: 'article',
+    },
+    custom: [
+      ...(baseMeta.custom || []),
+      // Learning resource-specific meta tags
+      {
+        name: 'resource-type',
+        content: 'learning-material',
+      },
+    ],
+  }
+}
+
+/**
+ * Helper function to generate an excerpt from HTML content
+ * 
+ * @param html - HTML content string
+ * @param maxLength - Maximum length of excerpt (default: 160)
+ * @returns Plain text excerpt
+ */
+function generateExcerpt(html: string, maxLength: number = 160): string {
+  // Strip HTML tags
+  const text = html.replace(/<[^>]*>/g, '')
+  
+  // Decode HTML entities
+  const decoded = text
+    .replace(/&nbsp;/g, ' ')
+    .replace(/&amp;/g, '&')
+    .replace(/&lt;/g, '<')
+    .replace(/&gt;/g, '>')
+    .replace(/&quot;/g, '"')
+    .replace(/&#039;/g, "'")
+  
+  // Trim to max length
+  if (decoded.length <= maxLength) {
+    return decoded
+  }
+  
+  // Truncate at word boundary
+  const truncated = decoded.substring(0, maxLength)
+  const lastSpace = truncated.lastIndexOf(' ')
+  
+  return truncated.substring(0, lastSpace > 0 ? lastSpace : maxLength) + '...'
+}
+
+/**
+ * Composable for fetching and applying Drupal node meta tags
+ * 
+ * @example
+ * ```vue
+ * <script setup lang="ts">
+ * import { useDrupalNodeMeta } from '@/composables/drupal-meta'
+ * import { ref, watch } from 'vue'
+ * 
+ * const props = defineProps<{ nodeId: string }>()
+ * const node = ref(null)
+ * 
+ * // Fetch node data from API
+ * // ...
+ * 
+ * // Apply meta tags when node is loaded
+ * useDrupalNodeMeta(node)
+ * </script>
+ * ```
+ */
+export function useDrupalNodeMeta(
+  nodeResult: { value: ArticleNode | PageNode | LearningResourceNode | null },
+  baseUrl?: string
+) {
+  const route = useRoute()
+  
+  // Determine which meta generator to use based on node type
+  const getMetaGenerator = (node: ArticleNode | PageNode | LearningResourceNode) => {
+    switch (node.type) {
+      case 'node--article':
+        return generateArticleContentMeta
+      case 'node--page':
+        return generatePageContentMeta
+      case 'node--learning_resource':
+        return generateLearningResourceMeta
+      default:
+        return generateDrupalNodeMeta
+    }
+  }
+
+  // Compute meta config based on current node
+  const metaConfig = computed(() => {
+    const node = nodeResult.value
+    if (!node) {
+      return {
+        title: 'Loading...',
+        description: '',
+      }
+    }
+    
+    const generator = getMetaGenerator(node)
+    return generator(node, baseUrl)
+  })
+
+  // Apply meta tags
+  useMeta(metaConfig, route)
+}