ios: offer creating a profile for a one-time invitation link

Adds "Add profile" to the picker reached from "Share profile" on a one-time
link. The new profile is routed through the existing selectedProfile path, so
the connection change and the switch cannot drift from picking an existing one.

The row sits outside the active-profile branch: inside it, it would disappear
whenever the active profile is filtered out by the search text.

apps/ios/Shared/Views/NewChat/NewChatView.swift

@@ -397,6 +397,8 @@ private struct ActiveProfilePicker: View {
     @State private var searchTextOrPassword = ""
     @State private var showIncognitoSheet = false
     @State private var incognitoFirst: Bool = false
+    @State private var showAddProfile = false
+    @State private var creatingProfile = false
     @State var selectedProfile: User
     var trimmedSearchTextOrPassword: String { searchTextOrPassword.trimmingCharacters(in: .whitespaces)}
 
@@ -558,6 +560,61 @@ private struct ActiveProfilePicker: View {
         }
     }
 
+    private var addProfileOption: some View {
+        Button {
+            showAddProfile = true
+        } label: {
+            HStack {
+                Image(systemName: "person.crop.circle.badge.plus")
+                    .resizable().scaledToFit().frame(width: 38, height: 38)
+                    .foregroundColor(theme.colors.primary)
+                Text("Add profile")
+                    .foregroundColor(theme.colors.primary)
+                Spacer()
+            }
+        }
+        .disabled(creatingProfile || switchingProfileByTimeout)
+    }
+
+    // Creates a profile for this invitation without activating it, then routes through
+    // the same selectedProfile path as picking an existing profile, so the connection
+    // change and the switch cannot drift apart.
+    private func createProfileForConnection(_ displayName: String, _ shortDescr: String?, _ image: String?) async throws {
+        // Atomic check-and-set on the main actor: a plain check-then-set leaves a window
+        // where two submits both pass, and @State must not be read off the main actor.
+        let alreadyCreating = await MainActor.run { () -> Bool in
+            if creatingProfile { return true }
+            creatingProfile = true
+            return false
+        }
+        if alreadyCreating { return }
+        defer { Task { @MainActor in creatingProfile = false } }
+        let profile = Profile(displayName: displayName, fullName: "", shortDescr: shortDescr, image: image)
+        let newUser = try apiCreateProfileKeepingActive(profile)
+        let users = try? listUsers()
+        await MainActor.run {
+            if let users = users { chatModel.users = users }
+            profiles = chatModel.users.map { $0.user }
+        }
+        if newUser.activeUser {
+            // Older core ignored keepActiveUser and switched instead - resync rather than
+            // attempting a connection change that would now fail.
+            try await changeActiveUserAsync_(newUser.userId, viewPwd: nil)
+            await MainActor.run {
+                alert = SomeAlert(
+                    alert: Alert(title: Text("Error changing chat profile")),
+                    id: "createProfileActivatedError"
+                )
+            }
+            return
+        }
+        await MainActor.run {
+            showAddProfile = false
+            selectedProfile = newUser
+            profileSwitchStatus = .switchingUser
+        }
+    }
+
     @ViewBuilder private func profilePicker() -> some View {
         let incognitoOption = Button {
             if !incognitoEnabled {
@@ -610,8 +667,26 @@ private struct ActiveProfilePicker: View {
                     profilerPickerUserOption(p)
                 }
             }
+
+            // Outside the branch above: inside it the row would disappear whenever the
+            // active profile is filtered out by the search text. Only offered when there
+            // is a connection to move to the new profile.
+            if contactConnection != nil {
+                addProfileOption
+            }
         }
         .opacity(switchingProfileByTimeout ? 0.4 : 1)
+        // Attached to the picker, not to the row: the row lives in a lazy container that
+        // may dispose it, taking the presented sheet with it. Not the root either - two
+        // .sheet modifiers on the same view conflict, and body already presents
+        // IncognitoHelp.
+        .sheet(isPresented: $showAddProfile) {
+            NavigationView {
+                CreateProfile(onSubmit: { displayName, shortDescr, image in
+                    try await createProfileForConnection(displayName, shortDescr, image)
+                })
+            }
+        }
     }
 }