fix(swift-sdk): Fix teardown params and WebView lifecycle

- Send params: [:] instead of nil (TS SDK expects object, not undefined)
- Use strong reference for WebView in transport to prevent premature dealloc
- Add guard for nil transport with proper error
- Add debug logging to sendRequest

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: ochafik

swift/Sources/McpApps/AppBridge.swift

@@ -232,7 +232,7 @@ public actor AppBridge {
     }
 
     public func sendResourceTeardown() async throws -> McpUiResourceTeardownResult {
-        _ = try await sendRequest(method: "ui/resource-teardown", params: nil)
+        _ = try await sendRequest(method: "ui/resource-teardown", params: [:])
         return McpUiResourceTeardownResult()
     }
 
@@ -247,12 +247,20 @@ public actor AppBridge {
         nextRequestId += 1
         let request = JSONRPCRequest(id: id, method: method, params: params)
 
+        guard transport != nil else {
+            print("[AppBridge] sendRequest failed: transport is nil")
+            throw BridgeError.disconnected
+        }
+
         return try await withCheckedThrowingContinuation { continuation in
             pendingRequests[id] = continuation
             Task {
                 do {
+                    print("[AppBridge] Sending request: \(method)")
                     try await transport?.send(.request(request))
+                    print("[AppBridge] Request sent successfully, waiting for response...")
                 } catch {
+                    print("[AppBridge] Transport send failed: \(error)")
                     pendingRequests.removeValue(forKey: id)?.resume(throwing: error)
                 }
             }

swift/Sources/McpApps/Transport/WKWebViewTransport.swift

@@ -25,7 +25,8 @@ public actor WKWebViewTransport: McpAppsTransport {
     private var messageHandler: MessageHandlerProxy?
 
     // Store webView reference for MainActor access
-    @MainActor private weak var webView: WKWebView?
+    // Note: Using strong reference to ensure webView stays alive for teardown messages
+    @MainActor private var webView: WKWebView?
 
     public let incoming: AsyncThrowingStream<JSONRPCMessage, Error>
 
@@ -109,6 +110,7 @@ public actor WKWebViewTransport: McpAppsTransport {
         await MainActor.run {
             webView?.configuration.userContentController.removeScriptMessageHandler(forName: name)
             webView?.configuration.userContentController.removeAllUserScripts()
+            webView = nil  // Release strong reference
         }
 
         messageHandler = nil