fix(fxt): robust ibapi handshake retry and config test isolation

- ibapi handshake: retry once after 1s on first failure (IB Gateway
  needs time to release stale client_id slots after disconnection)
- test_load_nonexistent_config → test_load_config_succeeds: remove
  default-value assertions that fail when ~/.foxhunt/config.toml exists
  (defaults already tested by test_serde_defaults and test_default_config)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

bin/fxt/src/commands/broker.rs

@@ -151,19 +151,52 @@ async fn check_tcp_connect(host: &str, port: u16) -> CheckResult {
 }
 
 /// Full ibapi handshake (blocking, runs on spawn_blocking).
+/// Retries once after 1s if the first attempt fails (IB Gateway may need time
+/// to release a stale client_id slot after a previous disconnection).
 #[cfg(feature = "broker-check")]
 async fn check_ibapi_handshake(host: &str, port: u16, client_id: i32) -> CheckResult {
     let addr = format!("{host}:{port}");
     let start = Instant::now();
-    match tokio::task::spawn_blocking(move || ibapi::Client::connect(&addr, client_id)).await {
+
+    let a1 = addr.clone();
+    let first = tokio::task::spawn_blocking(move || ibapi::Client::connect(&a1, client_id)).await;
+
+    match first {
         Ok(Ok(client)) => {
-            let server_version = client.server_version();
-            // client is dropped here which disconnects
+            let sv = client.server_version();
+            return CheckResult {
+                name: "ibapi handshake".to_owned(),
+                passed: true,
+                detail: format!(
+                    "client_id={client_id}, server v{sv} ({}ms)",
+                    start.elapsed().as_millis()
+                ),
+                duration_ms: start.elapsed().as_millis(),
+            };
+        }
+        Ok(Err(_)) => {
+            // Retry once — IB Gateway may need time to release stale client_id slot
+            tokio::time::sleep(std::time::Duration::from_secs(1)).await;
+        }
+        Err(e) => {
+            return CheckResult {
+                name: "ibapi handshake".to_owned(),
+                passed: false,
+                detail: format!("Task join error: {e}"),
+                duration_ms: start.elapsed().as_millis(),
+            };
+        }
+    }
+
+    let a2 = addr;
+    match tokio::task::spawn_blocking(move || ibapi::Client::connect(&a2, client_id)).await {
+        Ok(Ok(client)) => {
+            let sv = client.server_version();
             CheckResult {
                 name: "ibapi handshake".to_owned(),
                 passed: true,
                 detail: format!(
-                    "client_id={client_id}, server v{server_version} ({}ms)",
+                    "client_id={client_id}, server v{sv} ({}ms, retry)",
                     start.elapsed().as_millis()
                 ),
                 duration_ms: start.elapsed().as_millis(),

bin/fxt/src/config.rs

@@ -226,17 +226,11 @@ mod tests {
     }
 
     #[test]
-    fn test_load_nonexistent_config() {
-        // This should return default config without error when file doesn't exist
+    fn test_load_config_succeeds() {
+        // load() should always succeed: returns file contents if present, defaults otherwise.
+        // Default-value assertions live in test_serde_defaults and test_default_config.
         let result = TliConfig::load();
         assert!(result.is_ok());
-        let config = result.unwrap();
-
-        // When config file doesn't exist, load() returns Self::default()
-        // which should have all default values
-        assert_eq!(config.api_gateway_url, "http://localhost:50051");
-        assert_eq!(config.log_level, "info");
-        assert_eq!(config.token_storage, "keyring");
     }
 
     #[test]