fix: complete rebranding from Hiddify to Umbrix in packages

Package metadata changes:
- Package name: hiddify → umbrix
- Display name: Hiddify → Umbrix
- Maintainer: hiddify → umbrix
- Email: linux@hiddify.com → linux@umbrix.com
- Keywords: updated to Umbrix, Clash, Sing-box
- Install message: 'Installed Umbrix VPN'
- Icon: using logo/ic_launcher_playstore.png

All Linux packages (DEB/RPM/AppImage) now fully rebranded.
Note: HiddifyCli binary name preserved for compatibility.

linux/packaging/appimage/make_config.yaml

@@ -1,18 +1,17 @@
-display_name: Hiddify
+display_name: Umbrix
 
-icon: ./assets/images/source/ic_launcher_border.png
+icon: ./logo/ic_launcher_playstore.png
 
 keywords:
-  - Hiddify
+  - Umbrix
   - Proxy
   - VPN
   - V2ray
-  - Nekoray
   - Xray
-  - Psiphon
-  - OpenVPN
+  - Clash
+  - Sing-box
 
-generic_name: Hiddify
+generic_name: Umbrix
 
 actions:
   - name: Start