fix: re-fetch instrument data after login for new machines

Auth success handler now eagerly loads instrumentSelectorData
via listPlugins + getSoundfontCatalog. The mount-time useEffect
runs before auth token is set, so it silently fails on new machines.

app/static/js/app.jsx

@@ -7593,6 +7593,22 @@ const App = () => {
             window.__soundfontCatalog = cat;
           }).catch(() => {});
         } catch (e) { }
+        // Re-fetch instrument data after auth (useEffect on mount runs before token is set)
+        try {
+          window.SonicAPI.listPlugins().then(async data => {
+            try {
+              const catResp = await window.SonicAPI.getSoundfontCatalog?.() ?? await fetch('/api/v1/plugins/soundfonts/catalog').then(r => r.json());
+              const catalog = catResp.full_catalog || {};
+              data.soundfonts = (data.soundfonts || []).map(sf => {
+                const sfId = sf.id.replace('sf_', '');
+                const catEntry = catalog[sfId.toLowerCase()] || catalog[sfId];
+                if (catEntry && catEntry.instruments) return { ...sf, presets: catEntry.instruments };
+                return sf;
+              });
+            } catch (e) { console.warn('Catalog fetch error:', e); }
+            setInstrumentSelectorData(data);
+          }).catch(() => {});
+        } catch (e) { }
       })();
     }
   };