fix: move service_signatures.json inside app package and bump to 1.3.3

The file was in /app/data/ which gets overwritten by the Docker volume
mount (backend_data:/app/data), making it invisible at runtime and
causing scan failures on fresh installs. Moved to /app/app/data/ so
it stays baked into the image.

frontend/package.json

@@ -1,7 +1,7 @@
 {
   "name": "frontend",
   "private": true,
-  "version": "1.3.2",
+  "version": "1.3.3",
   "type": "module",
   "scripts": {
     "dev": "vite",