fix(transport): replace Tauri listen() to avoid unlisten race crashing on WKWebView

Call plugin:event|listen/unlisten directly and guard the client-side listener
registry cleanup, so unsubscribe always reaches the backend even when the
registration eval has not yet populated window.__TAURI_EVENT_LISTENERS__.
Prevents the intermittent `listeners[eventId].handlerId` TypeError and the
resulting leaked listener.

src/contexts/acp-connections-context.tsx

@@ -2042,11 +2042,7 @@ export function AcpConnectionsProvider({ children }: { children: ReactNode }) {
     })
       .then((fn) => {
         if (cancelled) {
-          try {
-            fn()
-          } catch {
-            // Tauri listener may not be fully registered yet
-          }
+          fn()
         } else {
           unlisten = fn
           listenerReadyRef.current = true
@@ -2066,11 +2062,7 @@ export function AcpConnectionsProvider({ children }: { children: ReactNode }) {
         clearTimeout(flushTimerRef.current)
         flushTimerRef.current = null
       }
-      try {
-        unlisten?.()
-      } catch {
-        // Tauri listener may not be fully registered yet
-      }
+      unlisten?.()
     }
   }, [bufferUnmappedEvent, handleMappedEvent, resolveListenerReadyWaiters])
 

src/lib/transport/tauri-transport.ts

@@ -1,17 +1,58 @@
 import type { Transport, UnsubscribeFn } from "./types"
 
+type TauriEventListenersWindow = {
+  __TAURI_EVENT_PLUGIN_INTERNALS__?: {
+    unregisterListener?: (event: string, eventId: number) => void
+  }
+}
+
 export class TauriTransport implements Transport {
   async call<T>(command: string, args?: Record<string, unknown>): Promise<T> {
     const { invoke } = await import("@tauri-apps/api/core")
     return invoke(command, args)
   }
 
+  // Bypasses `@tauri-apps/api/event#listen` to sidestep an intermittent race:
+  // Tauri's Rust `listen_js` schedules a fire-and-forget eval that populates
+  // `window.__TAURI_EVENT_LISTENERS__[event][eventId]` and, separately, returns
+  // `eventId` via the invoke response. On WKWebView the two can arrive out of
+  // order. When cleanup fires before the eval lands, the built-in `_unlisten`
+  // throws synchronously on `listeners[eventId].handlerId` — and because that
+  // throw happens BEFORE `await invoke('plugin:event|unlisten')`, the backend
+  // listener is never removed (handler + payload buffering leak).
+  //
+  // We own the eventId here so we can always issue the backend unlisten, even
+  // when the client-side registry entry hasn't appeared yet.
   async subscribe<T>(
     event: string,
     handler: (payload: T) => void
   ): Promise<UnsubscribeFn> {
-    const { listen } = await import("@tauri-apps/api/event")
-    return listen<T>(event, (e) => handler(e.payload))
+    const { invoke, transformCallback } = await import("@tauri-apps/api/core")
+    const handlerId = transformCallback((e: { payload: T }) => {
+      handler(e.payload)
+    })
+    const eventId = await invoke<number>("plugin:event|listen", {
+      event,
+      target: { kind: "Any" },
+      handler: handlerId,
+    })
+
+    let unlistened = false
+    return () => {
+      if (unlistened) return
+      unlistened = true
+      try {
+        const internals = (window as unknown as TauriEventListenersWindow)
+          .__TAURI_EVENT_PLUGIN_INTERNALS__
+        internals?.unregisterListener?.(event, eventId)
+      } catch {
+        // Registration eval has not landed yet; server-side unlisten below
+        // still clears the listener so events stop flowing.
+      }
+      // Fire-and-forget: callers expect a sync unsubscribe, and a failure here
+      // only means the backend already forgot this listener.
+      invoke("plugin:event|unlisten", { event, eventId }).catch(() => {})
+    }
   }
 
   isDesktop(): boolean {