fix: constrain canonical head links to safe attributes

Nuxt recommends useHeadSafe when head data is derived from input because it restricts rendered head fields to a safe attribute whitelist. The canonical composable builds links from route and optional content-derived markdown paths, and useHeadSafe still allows the rel, href, type, and related link attributes this helper emits.

Docs: https://nuxt.com/docs/4.x/api/composables/use-head-safe

Author: onmax

app/composables/useCanonical.ts

@@ -10,7 +10,7 @@ export function useCanonical(markdownAlternate?: MaybeRefOrGetter<string | null
   const route = useRoute()
   const site = useSiteConfig()
 
-  useHead({
+  useHeadSafe({
     link: computed(() => {
       const links: Link[] = [
         { rel: 'canonical', href: joinURL(site.url, route.path) }