feat(frontend): rich OG metadata + dynamic page titles across all routes

thoughts-frontend/app/thoughts/[thoughtId]/page.tsx

@@ -1,5 +1,7 @@
+import type { Metadata } from "next";
 import { cookies } from "next/headers";
 import {
+  getThoughtById,
   getThoughtThread,
   getUserProfile,
   getMe,
@@ -14,6 +16,42 @@ interface ThoughtPageProps {
   params: Promise<{ thoughtId: string }>;
 }
 
+function stripHtml(html: string) {
+  return html.replace(/<[^>]*>/g, "").trim();
+}
+
+export async function generateMetadata({
+  params,
+}: ThoughtPageProps): Promise<Metadata> {
+  const { thoughtId } = await params;
+  const thought = await getThoughtById(thoughtId, null).catch(() => null);
+  if (!thought) return { title: "Thought" };
+
+  const author = thought.author.displayName || thought.author.username;
+  const preview = stripHtml(thought.content).slice(0, 120);
+  const description = preview || `A thought by ${author}`;
+
+  return {
+    title: `${author}: "${preview.slice(0, 60)}${preview.length > 60 ? "…" : ""}"`,
+    description,
+    openGraph: {
+      type: "article",
+      title: `${author} on Thoughts`,
+      description,
+      images: thought.author.avatarUrl
+        ? [{ url: thought.author.avatarUrl }]
+        : [],
+      publishedTime: thought.createdAt.toISOString(),
+    },
+    twitter: {
+      card: "summary",
+      title: `${author} on Thoughts`,
+      description,
+      images: thought.author.avatarUrl ? [thought.author.avatarUrl] : [],
+    },
+  };
+}
+
 function collectAuthors(thread: ThoughtThreadType): string[] {
   const authors = new Set<string>([thread.author.username]);
   for (const reply of thread.replies) {