feat: linkify also catches www.* and bare domain.tld/path URLs

The description linkifier only caught http(s):// URLs; extend it to www.* hosts and
bare domain.tld/path URLs (both get an https:// href prefix), so links like
www.amelielens.com and facebook.com/amelielensmusic become clickable too. A required
path + letters-only TLD keep false positives (version numbers, file names) out; bare
@handles and #hashtags stay plain (the platform is ambiguous).

frontend/src/lib/linkify.tsx

@@ -1,13 +1,20 @@
 import { Fragment, type ReactNode } from "react";
 
-// A bare http(s) URL: greedy up to whitespace/<, but don't swallow a trailing sentence
-// punctuation mark (so "…see https://x.com/y." links "https://x.com/y", not the dot).
-const URL_RE = /(https?:\/\/[^\s<]+[^\s<.,!?;:)\]}"'])/g;
+// Recognises three link shapes in plain text:
+//   1. explicit http(s):// URLs
+//   2. www.* bare hosts
+//   3. domain.tld/path bare URLs — the required path AND a letters-only TLD keep false positives
+//      (version numbers like "3.2/x", file names like "index.html") from matching.
+// The last matched char excludes trailing sentence punctuation, so "see foo.com/bar." links
+// "foo.com/bar" and leaves the period. Bare @handles are intentionally NOT linked — the platform
+// is ambiguous.
+const URL_RE =
+  /((?:https?:\/\/|www\.)[^\s<]+[^\s<.,!?;:)\]}"']|[a-z0-9-]+(?:\.[a-z0-9-]+)*\.[a-z]{2,}\/[^\s<]*[^\s<.,!?;:)\]}"'])/gi;
 
 /**
- * Turn bare http(s) URLs inside a plain-text string into clickable links that open in a new tab
- * (with a safe rel). Everything else is returned as text, so it composes with `whitespace-pre-wrap`
- * (line breaks preserved). Used for channel/video descriptions where links arrive as plain text.
+ * Turn bare URLs (http(s), www, or domain.tld/path) inside a plain-text string into links that open
+ * in a new tab (safe rel). Non-http matches get an https:// prefix on the href, but keep their
+ * original text. Everything else is returned as text, so it composes with `whitespace-pre-wrap`.
  */
 export function linkify(text: string): ReactNode[] {
   const out: ReactNode[] = [];
@@ -17,19 +24,20 @@ export function linkify(text: string): ReactNode[] {
   let m: RegExpExecArray | null;
   while ((m = URL_RE.exec(text)) !== null) {
     if (m.index > last) out.push(<Fragment key={key++}>{text.slice(last, m.index)}</Fragment>);
-    const url = m[0];
+    const raw = m[0];
+    const href = /^https?:\/\//i.test(raw) ? raw : `https://${raw}`;
     out.push(
       <a
         key={key++}
-        href={url}
+        href={href}
         target="_blank"
         rel="noopener noreferrer"
         className="text-accent hover:underline break-all"
       >
-        {url}
+        {raw}
       </a>,
     );
-    last = m.index + url.length;
+    last = m.index + raw.length;
   }
   if (last < text.length) out.push(<Fragment key={key++}>{text.slice(last)}</Fragment>);
   return out;