Fix update loop: read APP_VERSION from package.json v1.3.1

APP_VERSION was hardcoded as "1.1.29" in constants.ts causing the app
to always report the old version and re-trigger the update prompt.
Now reads version dynamically from package.json via import.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "real-debrid-downloader",
-  "version": "1.3.0",
+  "version": "1.3.1",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "real-debrid-downloader",
-      "version": "1.3.0",
+      "version": "1.3.1",
       "license": "MIT",
       "dependencies": {
         "adm-zip": "^0.5.16",