fix: default display level to 3 (half summary)

frontend/src/pages/SynthesisDetail.tsx

@@ -139,7 +139,7 @@ const SynthesisDetail: Component = () => {
   });
 
   // Display level for article cards (1=title only, 2=+2 lines, 3=+half, 4=full)
-  const [displayLevel, setDisplayLevel] = createSignal(4);
+  const [displayLevel, setDisplayLevel] = createSignal(3);
 
   // Export state
   const [exportingMarkdown, setExportingMarkdown] = createSignal(false);