perf(test): remove two avoidable waits from the check suite

happy-dom's Element.toString() serializes outerHTML, and Popper stringifies nodes while the app loads, so each browser runtime spent most of its startup serializing the document. The LAN pairing test's stale address was a bound socket that macOS leaves unanswered until the 2 s probe timeout; a listener that closes every connection fails at once on every platform.

src-tauri/Cargo.lock

@@ -9433,7 +9433,6 @@ dependencies = [
  "rustls",
  "serde",
  "serde_json",
- "socket2",
  "tokio",
  "tracing",
  "tt-contracts",

src-tauri/crates/tt-adapter-sync/Cargo.toml

@@ -37,7 +37,6 @@ mdns-sd = "0.21.3"
 
 [dev-dependencies]
 base64 = "0.23"
-socket2 = { version = "0.6", features = ["all"] }
 
 [target.'cfg(target_os = "macos")'.dev-dependencies]
 mdns-sd = "0.21.3"

src-tauri/crates/tt-adapter-sync/src/sync/lan/server.rs

@@ -397,7 +397,6 @@ mod tests {
     use async_trait::async_trait;
     use base64::Engine;
     use base64::engine::general_purpose::URL_SAFE_NO_PAD;
-    use socket2::{Domain, Protocol, Socket, Type};
     use tokio::sync::{Mutex, mpsc};
     use tt_contracts::lan_discovery::LanDiscoveryAnnouncement;
     use tt_ports::lan_sync::LanPairingClient;
@@ -700,17 +699,12 @@ mod tests {
             completions: Mutex::new(completions),
         });
         let events = recording_events();
-        // Reserve a non-listening port so the stale candidate fails without a timing race.
-        let unavailable = Socket::new(Domain::IPV4, Type::STREAM, Some(Protocol::TCP))
-            .expect("reserve stale address");
-        unavailable
-            .bind(&"127.0.0.1:0".parse::<SocketAddr>().unwrap().into())
+        // The stale candidate must fail at once while keeping its port reserved.
+        let stale = tokio::net::TcpListener::bind("127.0.0.1:0")
+            .await
             .expect("bind stale address");
-        let stale_address = unavailable
-            .local_addr()
-            .expect("stale address")
-            .as_socket()
-            .unwrap();
+        let stale_address = stale.local_addr().expect("stale address");
+        tokio::spawn(async move { while stale.accept().await.is_ok() {} });
         let handle = spawn_lan_sync_server(
             "127.0.0.1:0".parse().unwrap(),
             default_user_dir.clone(),

tests/browser/runtime.mjs

@@ -38,6 +38,8 @@ export function createBrowserRuntime() {
             return nodeName.get.call(this);
         },
     });
+    // Elements must stringify as in browsers, or Popper serializes the document during startup.
+    delete window.Element.prototype.toString;
     window.document.write(readFileSync(path.join(root, 'index.html'), 'utf8')
         .replace(/<script\b[^>]*>[\s\S]*?<\/script>/g, ''));
     for (const file of ['jquery-3.5.1.min.js', 'jquery-ui.min.js', 'jquery.transit.min.js',