tone3000 metadata capture: save .meta.json alongside downloaded models

- UI now sends full Tone3000 metadata on install (id, author,
  architecture, pack_name, description, thumbnail, etc.)
- Search results show size, architecture, and pack name
- Install endpoint saves a .meta.json file next to each .nam with:
  author, architecture, description, pack, thumbnail, download date
- Enables offline browsing of model provenance

src/web/server.py

@@ -1950,6 +1950,25 @@ class WebServer:
             path = await client.download_model(model)
             if not path:
                 raise HTTPException(status_code=500, detail="Download failed")
+            # Save metadata alongside the model file
+            import json
+            meta = {
+                "id": data.get("id"),
+                "name": data.get("name"),
+                "filename": data.get("filename"),
+                "size_bytes": data.get("size"),
+                "author": data.get("author"),
+                "author_avatar": data.get("author_avatar"),
+                "thumbnail": data.get("thumbnail"),
+                "tone_description": data.get("tone_description"),
+                "pack_name": data.get("pack_name"),
+                "architecture": data.get("architecture"),
+                "created_at": data.get("created_at"),
+                "download_date": datetime.datetime.now().isoformat(),
+                "source": "tone3000",
+            }
+            meta_path = path.with_suffix(".meta.json")
+            meta_path.write_text(json.dumps(meta, indent=2))
             # Refresh the model list via NAM host
             nam = self.deps.nam_host
             if nam: