fix: enable createUpdaterArtifacts for updater signatures

- Adds createUpdaterArtifacts: true to bundle config
- Enables generation of .sig files for all artifacts
- Fixes updater JSON generation for auto-update support

Author: Mohammod Al Amin Ashik

apps/desktop/src-tauri/tauri.conf.json

@@ -43,6 +43,7 @@
   },
   "bundle": {
     "active": true,
+    "createUpdaterArtifacts": true,
     "targets": "all",
     "icon": [
       "icons/32x32.png",