Beef up /my cold-visitor "Start here" panel for promoted-link traffic

The dashboard serves two audiences — the member and prospects who click a
promoted link. Expanded the cold-visitor intro into a proper "New here? Start
here" panel at the top: what it is + 3 get-started steps + CTAs (join under this
member / watch training / strategy), and reframes the member detail below as
live proof. Member's own view still hides it.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

public/my.js

@@ -65,7 +65,7 @@
       const seenBefore=d._priorId===String(d.id); // they've viewed this position before (likely their own)
       const dismissed=sessionStorage.getItem('ctb.introDismissed')==='1';
       if(intro){
-        if(!seenBefore&&!dismissed){intro.classList.remove('hidden');document.getElementById('coldIntroJoin').href='/join/'+d.id;}
+        if(!seenBefore&&!dismissed){intro.classList.remove('hidden');const cij=document.getElementById('coldIntroJoin');cij.href='/join/'+d.id;cij.textContent='See how to join under #'+d.id+' →';}
         else intro.classList.add('hidden');
       }
     }catch(e){}