plan: web previews for channels (#7022)

* plan: web previews for channels

* types for recipient side to support channel web previews and domain names

* fix

* migrations

* update schema and api types

* update schema

* rename migrations

* core: check member role

---------

Co-authored-by: Evgeny @ SimpleX Chat <259188159+evgeny-simplex@users.noreply.github.com>

apps/ios/SimpleXChat/ChatTypes.swift

@@ -2531,10 +2531,22 @@ public enum GroupType: Codable, Hashable {
     }
 }
 
+public struct PublicGroupAccess: Codable, Hashable {
+    public var groupWebPage: String?
+    public var groupDomain: String?
+    public var domainWebPage: Bool = false
+    public var allowEmbedding: Bool = false
+}
+
+public struct RelayCapabilities: Codable, Hashable {
+    public var baseWebUrl: String?
+}
+
 public struct PublicGroupProfile: Codable, Hashable {
     public var groupType: GroupType
     public var groupLink: String
     public var publicGroupId: String
+    public var publicGroupAccess: PublicGroupAccess?
 }
 
 public struct GroupProfile: Codable, NamedChat, Hashable {
@@ -2703,6 +2715,7 @@ public struct GroupRelay: Identifiable, Decodable, Equatable, Hashable {
     public var userChatRelay: UserChatRelay
     public var relayStatus: RelayStatus
     public var relayLink: String?
+    public var relayCap: RelayCapabilities
     public var id: Int64 { groupRelayId }
 }