Signals in a folder of their own in the feed list, as an OPML's feeds are (#255)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/feedpage.ts

@@ -5,6 +5,7 @@ function renderFeed(){
   box.classList.remove('plain');
   const v=VIEWS[S.feed ?? ''];
   if(v&&v.url) return renderListed(v);
+  if(S.feed===SIGNALS) return renderSignals();
   const f=v?null:S.feeds.find(x=>x.id===S.feed);
   const sg=signalOf(S.feed);
   $<HTMLButtonElement>('#tbRemove').disabled=!f;