fix: catalog lookup uses lowercased key for merge

- catalog keys are lowercased (soundfont_inspector: .lower())
- sf.id from _scan_soundfonts has original case (SGM_v2.01)
- Use catalog[sfId.toLowerCase()] || catalog[sfId] to match both

app/static/js/app.jsx

@@ -6542,7 +6542,8 @@ const App = () => {
           // Merge presets into each soundfont entry
           data.soundfonts = (data.soundfonts || []).map(sf => {
             const sfId = sf.id.replace('sf_', '');
-            const catEntry = catalog[sfId];
+            // Catalog keys are lowercased by soundfont_inspector
+            const catEntry = catalog[sfId.toLowerCase()] || catalog[sfId];
             if (catEntry && catEntry.instruments) {
               return { ...sf, presets: catEntry.instruments };
             }