feat(blog): add dynamic blog post rendering with i18n support and error handling in [slug].vue

app/pages/blog/[slug].vue

@@ -2,14 +2,14 @@
 const { locale } = useI18n()
 const route = useRoute()
 
-const slug = Array.isArray(route.params.slug) ? route.params.slug.join('/') : route.params.slug
+const slug = route.params.slug as string
 const isFr = locale.value === 'fr'
-const collection = isFr ? 'blog_fr' : 'blog_en'
-// blog_fr prefix = /fr/blog, blog_en prefix = /en/blog (aligned with content.config.ts)
 const path = isFr ? `/fr/blog/${slug}` : `/en/blog/${slug}`
 
 const { data: page } = await useAsyncData(`blog-${locale.value}-${slug}`, () =>
-  queryCollection(collection).path(path).first()
+  isFr
+    ? queryCollection('blog_fr').path(path).first()
+    : queryCollection('blog_en').path(path).first()
 )
 
 if (!page.value) {