SimpleX names v2: Android, desktop and iOS UIs

The names hub and the buy / gift / receive / renew / recovery-key flows
across the Kotlin multiplatform app and the iOS Swift app. Stacked on the
core PR. iOS is written but unbuilt: it needs a Mac build (no iOS job in
CI) and a core lib rebuilt from the new simplexmq pin; expect
MsgContent.assetTransfer exhaustiveness one-liners and a few accessor
fixes on first xcodebuild.

apps/ios/Shared/Views/UserSettings/SimplexNames/WalletSetupView.swift

@@ -0,0 +1,34 @@
+import SwiftUI
+import SimpleXChat
+
+// How this profile gets its recovery key, asked once. Sharing the key across
+// profiles is the default because it means one thing to write down. A separate
+// key exists for a profile kept deliberately apart.
+struct WalletSetupView: View {
+    @Environment(\.dismiss) var dismiss
+    let hasOtherSeed: Bool
+    @State private var busy = false
+
+    var body: some View {
+        List {
+            Section {
+                if hasOtherSeed {
+                    Button { setup("existing") } label: { Label("Use the recovery key I already have", systemImage: "checkmark").foregroundColor(.accentColor) }
+                }
+                Button { setup("new") } label: {
+                    Label(hasOtherSeed ? "Give this profile its own recovery key" : "Create a recovery key", systemImage: "plus").foregroundColor(.accentColor)
+                }
+                NavigationLink { ImportRecoveryKeyView() } label: { Label("Restore names from a recovery key", systemImage: "square.and.arrow.down") }
+            } footer: {
+                Text(hasOtherSeed
+                    ? "Using the key you already have means one set of words to write down, and it covers every profile. A separate key keeps this profile's names unconnected to your others, but is a second thing to keep safe."
+                    : "You will be shown the key afterwards. Write it down — it is the only way to get your names back if you lose this device.")
+            }
+        }
+        .navigationTitle("Set up names for this profile")
+    }
+
+    private func setup(_ arg: String) {
+        Task { busy = true; defer { busy = false }; if await apiNameSetup(arg) { await MainActor.run { dismiss() } } }
+    }
+}