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/src/rpc_service/api.rs

@@ -70,6 +70,11 @@ impl<T: TunnelListener + 'static> ApiRpcServer<T> {
         self.rpc_server.serve().await?;
         Ok(self)
     }
+
+    pub fn with_rx_timeout(mut self, timeout: Option<std::time::Duration>) -> Self {
+        self.rpc_server.set_rx_timeout(timeout);
+        self
+    }
 }
 
 impl<T: TunnelListener + 'static> Drop for ApiRpcServer<T> {

easytier/src/rpc_service/logger.rs

@@ -26,7 +26,7 @@ impl LoggerRpcService {
         }
     }
 
-    fn string_to_log_level(level_str: &str) -> LogLevel {
+    pub fn string_to_log_level(level_str: &str) -> LogLevel {
         match level_str.to_lowercase().as_str() {
             "off" | "disabled" => LogLevel::Disabled,
             "error" => LogLevel::Error,