fix: add repository/author to desktop package.json, use --publish never in CI

electron-builder auto-detects CI and tries to publish to a release,
requiring a repository field and failing when none is found.
- Add repository and author fields to desktop/package.json
- Pass --publish never to electron-builder in the workflow so it builds
  installers without attempting any publish step

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

.gitea/workflows/docker-build.yml

@@ -97,16 +97,11 @@ jobs:
 
       - name: Build Linux AppImage
         working-directory: desktop
-        env:
-          # electron-builder reads this to avoid interactive prompts
-          GH_TOKEN: unused
-        run: npx electron-builder --linux AppImage --x64
+        run: npx electron-builder --linux AppImage --x64 --publish never
 
       - name: Build Windows NSIS installer
         working-directory: desktop
-        env:
-          GH_TOKEN: unused
-        run: npx electron-builder --win nsis --x64
+        run: npx electron-builder --win nsis --x64 --publish never
 
       - uses: actions/upload-artifact@v4
         with: