fix: deduplicate soundfont scan + source label + delete only uploads

- _scan_soundfonts: dict-keyed by base_id to prevent duplicates
- Add 'source' field ('system' | 'upload') to each soundfont entry
- Delete endpoint: only allow deleting upload soundfonts (403 for system)
- Frontend: show (system)/(upload) tag, hide Delete for system fonts

app/api/v1/plugins.py

@@ -103,14 +103,16 @@ async def upload_soundfont(
 async def delete_soundfont(sf_id: str, current_user: dict = Depends(get_current_user)):
     base_id = sf_id.replace("sf_", "")
     deleted = False
-    for d in [UPLOAD_SF_DIR, os.path.join(os.path.dirname(os.path.dirname(os.path.dirname(__file__))), "static", "soundfonts")]:
+    for d in [UPLOAD_SF_DIR, os.path.join(os.path.dirname(os.path.dirname(os.path.dirname(__file__))), "static", "soundfonts"), SYSTEM_SF_DIR]:
         if not os.path.isdir(d):
             continue
         for f in os.listdir(d):
             if os.path.splitext(f)[0] == base_id:
+                # Skip system dir — only allow deleting uploads
+                if d == SYSTEM_SF_DIR:
+                    raise HTTPException(status_code=403, detail="System soundfonts cannot be deleted via this endpoint")
                 path = os.path.join(d, f)
                 os.remove(path)
-                # Remove associated .meta file
                 meta_path = os.path.join(d, os.path.splitext(f)[0] + ".meta")
                 if os.path.isfile(meta_path):
                     os.remove(meta_path)

app/core/vst_engine.py

@@ -163,12 +163,11 @@ class PluginManager:
         return plugins
 
     def _scan_soundfonts(self) -> list:
-        sfonts = []
-        dirs = [self.sf_dir]
+        sf_map = {}
+        dirs = [("system", self.sf_dir)]
         if self.upload_sf_dir and self.upload_sf_dir != self.sf_dir:
-            dirs.append(self.upload_sf_dir)
+            dirs.append(("upload", self.upload_sf_dir))
         
-        # Load metadata cache for upload soundfonts
         meta_cache = {}
         if self.upload_sf_dir and os.path.isdir(self.upload_sf_dir):
             for f in os.listdir(self.upload_sf_dir):
@@ -180,21 +179,28 @@ class PluginManager:
                     except Exception:
                         pass
         
-        for d in dirs:
+        for source, d in dirs:
             if not os.path.isdir(d):
                 continue
             for f in os.listdir(d):
                 if f.endswith(".sf2") or f.endswith(".sf3"):
                     base_id = os.path.splitext(f)[0]
+                    if base_id in sf_map:
+                        continue
                     meta = meta_cache.get(base_id, None)
                     if meta:
                         display_name = meta.get("original_name", f)
                     else:
-                        # Generate a friendly name from UUID: truncate to first 8 chars
                         short_id = base_id[:8] if len(base_id) > 8 else base_id
                         display_name = f"SoundFont_{short_id}"
-                    sfonts.append({"id": base_id, "name": display_name, "file": f, "display": os.path.splitext(display_name)[0][:40]})
-        return sfonts
+                    sf_map[base_id] = {
+                        "id": base_id,
+                        "name": display_name,
+                        "file": f,
+                        "display": os.path.splitext(display_name)[0][:40],
+                        "source": source
+                    }
+        return list(sf_map.values())
 
     def load_vst(self, plugin_name: str, preset_data: dict = None):
         if not HAS_PEDALBOARD:

app/static/js/app.jsx

@@ -3459,12 +3459,17 @@ const PluginManagerModal = ({ isOpen, onClose, pluginsData }) => {
                       React.createElement('div', { className: 'text-xs font-semibold text-slate-200' }, sf.display || sf.name || sf.id),
                       React.createElement('div', { className: 'text-[10px] text-zinc-500' }, sf.file || sf.name)
                     )
+                  ), React.createElement('div', {
+                    className: 'text-[10px] text-zinc-500'
+                  }, sf.file || sf.name, ' ', React.createElement('span', {
+                    className: sf.source === 'system' ? 'text-blue-400' : 'text-amber-500'
+                  }, sf.source === 'system' ? '(system)' : '(upload)'))
                 ),
                 React.createElement('div', { className: 'flex items-center gap-2' },
-                    React.createElement('button', {
+                  sf.source === 'upload' ? React.createElement('button', {
                     onClick: () => setSfToDelete(sf),
                     className: 'text-[10px] text-zinc-500 hover:text-red-400 opacity-0 group-hover:opacity-100 transition px-2 py-1'
-                    }, 'Delete')
+                  }, 'Delete') : React.createElement('span', { className: 'text-[10px] text-zinc-700' }, 'System')
                   )
                 )
               )