Shorten thread route from /thread to /t

All internal links (tiles, prev/next nav, comments, notifications,
breadcrumb, dropzone route check) point to /t/<id>. A global route
middleware permanently redirects old /thread/<id> URLs including
query string and comment anchor.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

app/pages/t/[id].vue

@@ -598,7 +598,7 @@ async function deleteComment(commentId: number) {
             class="absolute left-2 top-1/2 -translate-y-1/2 shadow opacity-80 hover:opacity-100"
             as-child
           >
-            <NuxtLink :to="`/thread/${data.newerId}`" :aria-label="$t('thread.newer')">
+            <NuxtLink :to="`/t/${data.newerId}`" :aria-label="$t('thread.newer')">
               <Icon name="ph:caret-left-fill" class="size-5" />
             </NuxtLink>
           </Button>
@@ -609,7 +609,7 @@ async function deleteComment(commentId: number) {
             class="absolute right-2 top-1/2 -translate-y-1/2 shadow opacity-80 hover:opacity-100"
             as-child
           >
-            <NuxtLink :to="`/thread/${data.olderId}`" :aria-label="$t('thread.older')">
+            <NuxtLink :to="`/t/${data.olderId}`" :aria-label="$t('thread.older')">
               <Icon name="ph:caret-right-fill" class="size-5" />
             </NuxtLink>
           </Button>

app/pages/user/[id].vue

@@ -313,7 +313,7 @@ const timeAgo = useTimeAgo()
             <NuxtLink
               v-for="comment in comments.items"
               :key="comment.id"
-              :to="`/thread/${comment.uploadId}#comment-${comment.id}`"
+              :to="`/t/${comment.uploadId}#comment-${comment.id}`"
               class="flex items-center gap-3 px-3 py-2.5 text-sm transition-colors hover:bg-accent"
             >
               <NuxtImg