net10, the refactor finished, and federation that works

The tree had not compiled since its first commit: Group, DmGroup and
IGroupUsersService were referenced and never written, an IDE rename had
turned the user-settings DTO into the ViewAvatarServer enum, and the settings
were saved as an entity they no longer were.

Built now:
- Group (an ActivityPub Group actor with its own keys, members, invitation
  code and optional password) and DmGroup (a conversation), with
  /clientapi/group/{list,insert,update,join,leave,approve}.
- Posts and DMs: /clientapi/post/{list,insert,delete}, /clientapi/dm/{list,insert};
  DM recipients are local usernames or user@host handles resolved by WebFinger.
- Invitation sign-up and login against the group's invitation code, checking
  the password before any account is created.
- Federation: WebFinger, NodeInfo 2.0, actors at /peasants/{name} (Person,
  Group, and an Application instance actor) with SPKI keys, draft-cavage
  RSA-SHA256 HTTP signatures both ways, an inbox handling Follow (+Accept),
  Undo, Create, Delete and Update, an outbox, notes at /posts/{id}, and a
  persisted, retried, signed delivery queue. A post to a group is announced
  by the group to its followers (FEP-1b12).
- The unused, broken typed ActivityPub models are replaced by a renderer;
  NSign's HMAC setup, which could not federate, is gone.

Upgrade: net10.0, MongoDB.Entities 25.1 (instance DB API, Standard GUIDs),
Swashbuckle 10 / OpenApi 2, Serilog.AspNetCore 10, MailKit 4.18,
PasswordGenerator 3. The JWT keys are 64 bytes (IdentityModel 8 refuses
shorter for HS512). Production runs its own mongod on 127.0.0.1:27022, as
Sintopia's apps do, and deploys to privapub.thepra.dev from the build runner.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012CzABvBkbcFqoHdmi8b9WB

PrivaPub.ClientModels/User/Avatar/ViewAvatar.cs

@@ -1,10 +1,12 @@
-using System.Text.Json.Serialization;
+using System.Text.Json.Serialization;
 
 namespace PrivaPub.ClientModels.User.Avatar
 {
 	[JsonSerializable(typeof(ViewAvatar))]
 	public class ViewAvatar
 	{
+		public string Id { get; set; }
+		public string Handle { get; set; }
 		public string Url { get; set; }//url
 		public string Name { get; set; }//name
 		public string UserName { get; set; }//preferredUsername

PrivaPub.ClientModels/User/JwtUser.cs

@@ -1,4 +1,4 @@
-namespace PrivaPub.ClientModels.User
+namespace PrivaPub.ClientModels.User
 {
 	public class JwtUser
 	{
@@ -8,6 +8,6 @@
 		public List<string> Policies { get; set; } = new();
 		public string Token { get; set; }
 		public long Expiration { get; set; }
-		public ViewAvatarServer UserSettings { get; set; } = new();
+		public ViewUserSettings UserSettings { get; set; } = new();
 	}
 }

PrivaPub.ClientModels/User/ViewUserSettings.cs

@@ -0,0 +1,25 @@
+using PrivaPub.ClientModels.Resources;
+
+using System.ComponentModel.DataAnnotations;
+
+namespace PrivaPub.ClientModels.User
+{
+	public class ViewUserSettings
+	{
+		[Required(ErrorMessageResourceName = "Required", ErrorMessageResourceType = typeof(ErrorsResource)),
+				Display(Name = nameof(LanguageCode), ResourceType = typeof(FieldsNameResource))]
+		public string LanguageCode { get; set; } = "en";
+
+		[Range(0, 359, ErrorMessageResourceName = nameof(Range), ErrorMessageResourceType = typeof(ErrorsResource))]
+		public short LightThemeIndexColour { get; set; } = 25;
+		[Range(0, 359, ErrorMessageResourceName = nameof(Range), ErrorMessageResourceType = typeof(ErrorsResource))]
+		public short DarkThemeIndexColour { get; set; } = 215;
+		[Range(-2, 359, ErrorMessageResourceName = nameof(Range), ErrorMessageResourceType = typeof(ErrorsResource))]
+		public short IconsThemeIndexColour { get; set; } = 25;
+
+		public bool PreferSystemTheming { get; set; } = false;
+		public bool ThemeIsDarkMode { get; set; } = false;
+		public bool ThemeIsLightGray { get; set; } = false;
+		public bool ThemeIsDarkGray { get; set; } = false;
+	}
+}