Align Linux UI packaging deps with Wails v3 GTK4 stack

The Wails v3 tray is a pure DBus StatusNotifierItem implementation and no
longer links libappindicator (a Fyne-era dependency). Drop the
libayatana-appindicator runtime and build deps, and move the rpm package
and dev-dependency docs onto the GTK4 / WebKitGTK 6.0 stack that the
default (non-gtk3) build actually links against.

client/ui/build/linux/nfpm/nfpm.yaml

@@ -24,24 +24,24 @@ contents:
   - src: "./build/linux/netbird-ui.desktop"
     dst: "/usr/share/applications/netbird-ui.desktop"
 
-# Default dependencies for Debian 12/Ubuntu 22.04+ with WebKit 4.1
+# Default dependencies for the GTK4 + WebKitGTK 6.0 stack (Ubuntu 24.04+ / Debian 13+)
 depends:
-  - libgtk-3-0
-  - libwebkit2gtk-4.1-0
+  - libgtk-4-1
+  - libwebkitgtk-6.0-4
 
-# Distribution-specific overrides for different package formats and WebKit versions
+# Distribution-specific overrides for different package formats
 overrides:
-  # RPM packages for RHEL/CentOS/AlmaLinux/Rocky Linux (WebKit 4.0)
+  # RPM packages for Fedora / RHEL / AlmaLinux / Rocky Linux
   rpm:
     depends:
-      - gtk3
-      - webkit2gtk4.1
-  
-  # Arch Linux packages (WebKit 4.1)  
+      - gtk4
+      - webkitgtk6.0
+
+  # Arch Linux packages
   archlinux:
     depends:
-      - gtk3
-      - webkit2gtk-4.1
+      - gtk4
+      - webkitgtk-6.0
 
 # scripts section to ensure desktop database is updated after install
 scripts: