fix(webui): 修复首次打开慢时多次点击导致的竞态报错

open_kimi_web_embedded 加 launch_lock 串行化并发调用，拿锁后重查单例；
oneshot 在锁内等待主线程建窗完成，封死命令返回后的残留空档。
spawned_by_me 门控失败路径的 server 清理，复用的 server 不再被误杀；
spawn 前用 try_wait 检查已有子进程避免覆盖泄漏。前端两个打开按钮加
busy 态防重入（打开中...）。

src-tauri/src/commands.rs

@@ -1014,6 +1014,9 @@ pub struct KimiWebState {
     window: Mutex<Option<tauri::WebviewWindow>>,
     /// The `kimi web` child spawned by this app (None when reusing a server).
     child: Mutex<Option<std::process::Child>>,
+    /// Serializes `open_kimi_web_embedded` invocations: a rapid double-click
+    /// queues here instead of racing the window/server setup.
+    launch_lock: tokio::sync::Mutex<()>,
 }
 
 const KIMI_WEB_PORT: u16 = 58627;
@@ -1064,7 +1067,13 @@ pub async fn open_kimi_web_embedded(
     app: tauri::AppHandle,
     state: tauri::State<'_, KimiWebState>,
 ) -> Result<(), String> {
-    // Singleton: focus the existing window instead of creating a second one.
+    // Serialize concurrent invocations (rapid double-click): a second call
+    // waits here until the first has finished building the window, then
+    // re-checks the singleton below and focuses it instead.
+    let _guard = state.launch_lock.lock().await;
+
+    // Singleton (re-checked after acquiring the lock): focus the existing
+    // window instead of creating a second one.
     if let Ok(guard) = state.window.lock() {
         if let Some(w) = guard.as_ref() {
             if w.is_visible().unwrap_or(false) {
@@ -1075,8 +1084,21 @@ pub async fn open_kimi_web_embedded(
         }
     }
 
-    // Reuse an already-running server, otherwise spawn `kimi web --no-open`.
-    if !kimi_web_alive(Duration::from_millis(800)).await {
+    // Reuse the server this app spawned earlier (still running), or a server
+    // already running outside the app; only spawn when neither is present.
+    // `spawned_by_me` gates every failure-path kill, so a reused server is
+    // never terminated.
+    let mut spawned_by_me = false;
+    let mut child_running = false;
+    if let Ok(mut guard) = state.child.lock() {
+        // try_wait: Ok(None) = still running. Exited or unwaitable children
+        // are treated as gone so a fresh server is spawned below.
+        child_running = guard
+            .as_mut()
+            .map(|child| child.try_wait().map(|st| st.is_none()).unwrap_or(false))
+            .unwrap_or(false);
+    }
+    if !child_running && !kimi_web_alive(Duration::from_millis(800)).await {
         let mut cmd = std::process::Command::new("kimi");
         cmd.args(["web", "--no-open", "--port", &KIMI_WEB_PORT.to_string()]);
         #[cfg(windows)]
@@ -1091,6 +1113,7 @@ pub async fn open_kimi_web_embedded(
                 format!("failed to start `kimi web`: {e}")
             }
         })?;
+        spawned_by_me = true;
         if let Ok(mut guard) = state.child.lock() {
             *guard = Some(child);
         }
@@ -1098,37 +1121,68 @@ pub async fn open_kimi_web_embedded(
 
     // Wait for the server to come up (fresh start takes a moment).
     if !kimi_web_alive(Duration::from_secs(8)).await {
+        if spawned_by_me {
             kill_spawned_kimi_web(&state);
+        }
         return Err(format!("kimi web did not come up within 8s ({KIMI_WEB_ORIGIN})"));
     }
 
-    // Create the window on the main thread (required on macOS).
+    // Build the URL, then create the window on the main thread (required on
+    // macOS). The build result is awaited while still holding `launch_lock`,
+    // so a concurrent second invocation blocks here and then lands on the
+    // singleton re-check above once the window exists.
     let url: tauri::Url = match kimi_web_url().parse() {
         Ok(u) => u,
         Err(_) => return Err("invalid kimi web url".to_string()),
     };
-    let app = app.clone();
-    tauri::async_runtime::spawn(async move {
+    let (tx, rx) = tokio::sync::oneshot::channel::<Result<(), String>>();
     let builder_app = app.clone();
-        let _ = app.run_on_main_thread(move || {
-            match tauri::WebviewWindowBuilder::new(
-                &builder_app,
+    app.run_on_main_thread(move || {
+        let result = build_kimi_web_window(&builder_app, &url);
+        let _ = tx.send(result);
+    })
+    .map_err(|e| format!("failed to queue window creation: {e}"))?;
+    match rx.await {
+        Ok(result) => {
+            if let Err(e) = result {
+                // Window creation failed (e.g. label already taken): only stop
+                // the server when this invocation spawned it.
+                if spawned_by_me {
+                    kill_spawned_kimi_web(&state);
+                }
+                return Err(e);
+            }
+            Ok(())
+        }
+        // Sender dropped without a result (app shutting down, build never
+        // ran): never kill the server — a later invocation may reuse it.
+        Err(_) => Ok(()),
+    }
+}
+
+/// Build the embedded WebUI window on the main thread and track it for the
+/// singleton check. On success, wires close/destroy events to forget the
+/// window and stop the `kimi web` server this app spawned (reused servers are
+/// untouched).
+fn build_kimi_web_window(app: &tauri::AppHandle, url: &tauri::Url) -> Result<(), String> {
+    let window = tauri::WebviewWindowBuilder::new(
+        app,
         KIMI_WEB_WINDOW_LABEL,
-                tauri::WebviewUrl::External(url),
+        tauri::WebviewUrl::External(url.clone()),
     )
     .title("Kimi Code WebUI")
     .inner_size(1100.0, 750.0)
     .resizable(true)
     .center()
     .build()
-            {
-                Ok(window) => {
+    .map_err(|e| format!("failed to create kimi web window: {e}"))?;
+
     // Track the window for the singleton check.
-                    if let Ok(mut guard) = builder_app.state::<KimiWebState>().window.lock() {
+    if let Ok(mut guard) = app.state::<KimiWebState>().window.lock() {
         *guard = Some(window.clone());
     }
-                    // Clean up when the window closes: forget it and stop the
-                    // `kimi web` server we spawned (reused servers are untouched).
+    // Clean up when the window closes: forget it and stop the `kimi web`
+    // server we spawned (reused servers are untouched).
     let w = window.clone();
     window.on_window_event(move |event| match event {
         tauri::WindowEvent::Destroyed => {
@@ -1141,15 +1195,6 @@ pub async fn open_kimi_web_embedded(
         }
         _ => {}
     });
-                }
-                Err(_) => {
-                    // Window creation failed (e.g. rapid double-click racing
-                    // the singleton check): don't leak the server we spawned.
-                    kill_spawned_kimi_web(&builder_app.state::<KimiWebState>());
-                }
-            }
-        });
-    });
     Ok(())
 }
 /// Preference for Linux is AppImage (portable, no install). If the preferred

src/components/SubagentSettingsPage.tsx

@@ -162,6 +162,8 @@ export function SubagentSettingsPage({
   const [poolErrors, setPoolErrors] = useState<PoolValidationError[]>([]);
   /** Local draft for the "add pool entry" select (reset after each pick). */
   const [addSelection, setAddSelection] = useState("");
+  /** WebUI-open button in flight; disables both buttons while non-null. */
+  const [webuiBusy, setWebuiBusy] = useState<"embedded" | "browser" | null>(null);
 
   useEffect(() => {
     invoke<ExperimentalEnvStatus>("get_experimental_env_status")
@@ -371,29 +373,37 @@ export function SubagentSettingsPage({
           <div className="mt-3 flex flex-wrap gap-2">
             <button
               type="button"
+              disabled={webuiBusy !== null}
               onClick={async () => {
+                setWebuiBusy("embedded");
                 try {
                   await invoke("open_kimi_web_embedded");
                 } catch (err) {
                   alert(err instanceof Error ? err.message : String(err));
+                } finally {
+                  setWebuiBusy(null);
                 }
               }}
-              className="px-3 py-1.5 text-sm rounded bg-blue-600 text-white hover:bg-blue-500 focus:ring-2 focus:ring-blue-500 focus:outline-none"
+              className="px-3 py-1.5 text-sm rounded bg-blue-600 text-white hover:bg-blue-500 focus:ring-2 focus:ring-blue-500 focus:outline-none disabled:opacity-50 disabled:cursor-not-allowed"
             >
-              {t("openWebUIEmbedded")}
+              {webuiBusy === "embedded" ? t("webuiOpening") : t("openWebUIEmbedded")}
             </button>
             <button
               type="button"
+              disabled={webuiBusy !== null}
               onClick={async () => {
+                setWebuiBusy("browser");
                 try {
                   await invoke("open_kimi_web");
                 } catch (err) {
                   alert(err instanceof Error ? err.message : String(err));
+                } finally {
+                  setWebuiBusy(null);
                 }
               }}
-              className="px-3 py-1.5 text-sm border border-border rounded hover:bg-hover-2 focus:ring-2 focus:ring-blue-500 focus:outline-none"
+              className="px-3 py-1.5 text-sm border border-border rounded hover:bg-hover-2 focus:ring-2 focus:ring-blue-500 focus:outline-none disabled:opacity-50 disabled:cursor-not-allowed"
             >
-              {t("openWebUIBrowser")}
+              {webuiBusy === "browser" ? t("webuiOpening") : t("openWebUIBrowser")}
             </button>
           </div>
         </Card>

src/i18n/en.ts

@@ -528,6 +528,7 @@ export const enTranslations: Record<TranslationKey, string> = {
     "Open the new Web UI in an independent in-app window, or in your system browser (built into kimi-code 0.33+). Requires the kimi CLI on PATH.",
   openWebUIEmbedded: "Open in App",
   openWebUIBrowser: "Open in Browser",
+  webuiOpening: "Opening...",
 
   // Plugin marketplace
   pluginMarketplace: "Plugin Marketplace",

src/i18n/zh.ts

@@ -520,6 +520,7 @@ export const zhTranslations = {
     "以独立窗口在应用内打开新版 Web 界面，也可以选择在系统浏览器打开（kimi-code 0.33+ 内置 code-app；需要 kimi 命令在 PATH 中）。",
   openWebUIEmbedded: "在应用内打开",
   openWebUIBrowser: "在浏览器打开",
+  webuiOpening: "打开中...",
 
   // Plugin marketplace
   pluginMarketplace: "插件市场",