fix(tunnel): 移除 testkit 和 example 中残留的 idle_timeout 引用

apps/aether-gateway/examples/tunnel_runtime_harness.rs

@@ -25,13 +25,6 @@ struct Args {
     )]
     bind: String,
 
-    #[arg(
-        long,
-        default_value_t = 0,
-        env = "AETHER_TUNNEL_STANDALONE_PROXY_IDLE_TIMEOUT"
-    )]
-    proxy_idle_timeout: u64,
-
     #[arg(
         long,
         default_value_t = 15,
@@ -111,7 +104,6 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
         TunnelControlPlaneClient::new(args.app_base_url),
         TunnelConnConfig {
             ping_interval,
-            idle_timeout: Duration::from_secs(args.proxy_idle_timeout),
             outbound_queue_capacity,
         },
         args.max_streams,