Bugfixes, renames, create custom TextEditor, logic simplifications

Implementation/Peered/SetUsername/SetUserNameBottomSheetView.swift

@@ -2,7 +2,7 @@ import SwiftUI
 
 struct SetUserNameBottomSheetView: View {
   @State private var proposedUsername: String = ""
-  @Binding var username: String
+  @Binding var username: String?
 
   var body: some View {
     Form {