Fix: Downloads aus /data/downloads servieren + Electron Build fixen

- Downloads-Pfad von relativem App-Pfad auf DATA_DIR/downloads geändert
- Electron package.json: author Feld ergänzt (Squirrel-Requirement)
- forge.config.js: fehlende Icon-Referenzen entfernt

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

electron/forge.config.js

@@ -4,7 +4,6 @@ module.exports = {
   packagerConfig: {
     name: 'Gaming Hub',
     executableName: 'gaming-hub',
-    icon: path.join(__dirname, 'assets', 'icon'),
     asar: true,
   },
   makers: [
@@ -12,7 +11,6 @@ module.exports = {
       name: '@electron-forge/maker-squirrel',
       config: {
         name: 'gaming-hub-desktop',
-        setupIcon: path.join(__dirname, 'assets', 'icon.ico'),
       },
     },
     {