Settings: change the login's password, or delete the login

A Login section in Settings changes the root's password (the current one
given) and deletes the whole login, every persona with it, after its
password and an explicit "I understand"; the client then signs out. Both
use PrivaPub's existing /clientapi/user routes.

The e2e signs up a login of its own, changes its password and deletes it,
checking each against PrivaPub's login. Signing in now waits for either
the feed or an enabled persona chooser, so a login with one persona (which
goes on by itself) and a new persona's empty feed both sign in.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LsXgEaXee4GCU1hwYgPJXw

Services/AuthService.cs

@@ -114,6 +114,27 @@ namespace decePubClient.Services
 				await authStateProvider.SetSession(jwtUser, cancellationToken);
 		}
 
+		/// <summary>Changes the root's password, the current one given.</summary>
+		public async Task<WebResult> ChangePassword(UserPasswordForm form, CancellationToken cancellationToken = default)
+		{
+			using var response = await httpService.Post(APIs.ClientApi.POST_UpdatePassword, form, cancellationToken: cancellationToken);
+			if (!response.IsSuccessStatusCode)
+				return await response.Content.ReadWebResult(response.StatusCode, localizer, cancellationToken);
+
+			return new WebResult();
+		}
+
+		/// <summary>Deletes the root, its password given: every persona of it and everything public they had, here and, as
+		/// PrivaPub tells them, on the servers that hold it. The caller signs out afterwards.</summary>
+		public async Task<WebResult> DeleteAccount(RemoveSelfForm form, CancellationToken cancellationToken = default)
+		{
+			using var response = await httpService.Post(APIs.ClientApi.POST_DeleteAccount, form, cancellationToken: cancellationToken);
+			if (!response.IsSuccessStatusCode)
+				return await response.Content.ReadWebResult(response.StatusCode, localizer, cancellationToken);
+
+			return new WebResult();
+		}
+
 		/// <summary>Revokes every persona token the client holds, tells PrivaPub, then forgets the session and the local data.</summary>
 		public async Task Logout(CancellationToken cancellationToken = default)
 		{