feat(gui): add service and remote mode support (#1578)

This PR fundamentally restructures the EasyTier GUI, introducing support for service mode and remote mode, transforming it from a simple desktop application into a powerful network management terminal. This change allows users to persistently run the EasyTier core as a background service or remotely manage multiple EasyTier instances, greatly improving deployment flexibility and manageability.

easytier-gui/src-tauri/src/main.rs

@@ -1,5 +1,9 @@
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
 
-fn main() {
-    app_lib::run();
+fn main() -> std::process::ExitCode {
+    if std::env::args().count() > 1 {
+        app_lib::run_cli()
+    } else {
+        app_lib::run_gui()
+    }
 }