No admin by username, no Swagger in production, no exception text to clients

S14 and the privacy items of P0:
- signing up as "admin" no longer grants admin; `PrivaPub admin promote
  <root>` (and `demote`) does, run on the box against the configured
  database;
- Swagger is served in Development only;
- every service and controller answers "Something went wrong." where it
  used to send ex.Message, and the SMTP warnings no longer log the
  recipient's address;
- sign-up and login no longer log the IP, User-Agent and root id together;
- invitation sign-up takes the persona's own AvatarUserName (and optional
  AvatarName) instead of naming the avatar after the private login, and
  refuses a persona username equal to the login's. Invitation login uses
  the named persona, creating it if it is new;
- recovery mail comes from "PrivaPub", not collAnon's support address name.

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

PrivaPub/Infrastructure/Cli/AdminCommands.cs

@@ -0,0 +1,40 @@
+using MongoDB.Entities;
+
+using PrivaPub.ClientModels;
+using PrivaPub.Models.User;
+
+namespace PrivaPub.Infrastructure.Cli
+{
+	public static class AdminCommands
+	{
+		const string Usage = "usage: PrivaPub admin promote|demote <root username>";
+
+		public static async Task<int> Run(string[] args)
+		{
+			if (args is not [("promote" or "demote") and var verb, var userName])
+			{
+				Console.Error.WriteLine(Usage);
+				return 2;
+			}
+
+			userName = userName.ToLowerInvariant();
+			var user = await DB.Default.Find<RootUser>().Match(u => u.UserName == userName).ExecuteFirstAsync();
+			if (user == default)
+			{
+				Console.Error.WriteLine($"no root user '{userName}'");
+				return 1;
+			}
+
+			user.Policies.RemoveAll(p => p is Policies.IsAdmin or Policies.IsModerator);
+			if (verb == "promote")
+				user.Policies.AddRange(new[] { Policies.IsAdmin, Policies.IsModerator });
+			if (!user.Policies.Contains(Policies.IsUser))
+				user.Policies.Add(Policies.IsUser);
+			user.UpdatedAt = DateTime.UtcNow;
+			await DB.Default.SaveAsync(user);
+
+			Console.WriteLine($"{userName}: {string.Join(", ", user.Policies)}");
+			return 0;
+		}
+	}
+}