fix: resolve ambiguous toolbar(content:) in BusinessListView

Use explicit toolbar(content:) call instead of trailing closure to
disambiguate the SwiftUI toolbar modifier overload.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

PayfritBeacon/Views/BusinessListView.swift

@@ -39,13 +39,13 @@ struct BusinessListView: View {
                 }
             }
             .navigationTitle("Select Business")
-            .toolbar {
+            .toolbar(content: {
                 ToolbarItem(placement: .topBarTrailing) {
                     Button("Logout") {
                         appState.logout()
                     }
                 }
-            }
+            })
         }
         .task {
             await loadBusinesses()