fix(swift-host): Actually await teardown before removing card

The previous implementation spawned a Task but removed the card
immediately without waiting. Now properly awaits the teardown.

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

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

Author: ochafik

examples/basic-host-swift/Sources/BasicHostApp/ContentView.swift

@@ -24,7 +24,7 @@ struct ContentView: View {
                             ForEach(viewModel.activeToolCalls) { toolCall in
                                 ToolCallCard(
                                     toolCallInfo: toolCall,
-                                    onRemove: { viewModel.removeToolCall(toolCall) }
+                                    onRemove: { Task { await viewModel.removeToolCall(toolCall) } }
                                 )
                                 .id(toolCall.id)
                             }

examples/basic-host-swift/Sources/BasicHostApp/McpHostViewModel.swift

@@ -239,10 +239,8 @@ class McpHostViewModel: ObservableObject {
         }
     }
 
-    func removeToolCall(_ toolCall: ToolCallInfo) {
-        Task {
-            await toolCall.teardown()
-        }
+    func removeToolCall(_ toolCall: ToolCallInfo) async {
+        await toolCall.teardown()
         activeToolCalls.removeAll { $0.id == toolCall.id }
     }
 }