R6 moderation: roles, silence and suspension, bans that write nothing on the personas, deletions, report actions

Roles (user, moderator, administrator) from the CLI and /clientapi/admin/roots/{id}/role, never one's own nor the last
administrator. Silence keeps an account's posts out of public timelines, hashtags, trends, search and relays while its
followers still get them; suspension refuses and revokes a local persona's tokens, answers 404 for its posts and
collections, holds back every delivery and tells other servers nothing new, its actor unchanged; a suspended remote
account's activities are dropped and nothing goes to its own inbox (a shared one still serves its server). A banned
login's personas are held back in memory alone (Restrictions), so nothing pairs them in stored data. Personas and groups
are deleted one at a time (PersonaRemoval, GroupRemoval), by their login or an administrator with the password. Reports
resolve with an action and a note; posts are taken down, a remote copy hidden. Warnings reach the persona as Mastodon's
moderation_warning. Every staff act goes to the staff's log. Migration _020 limits posts from servers already silenced;
a restore keeps the moderation made since the backup.

Verified: interop.sh moderation gts mastodon with SecureMode, 194 passed; restore.sh, 25 passed, now with a suspension,
a silence and a takedown made after the backup.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WpVCoDeM1qUTRp4fXQdfof

PrivaPub/Controllers/ClientToServer/GroupController.cs

@@ -60,6 +60,27 @@ namespace PrivaPub.Controllers.ClientToServer
 		public async Task<IActionResult> Remove(GroupMembershipForm form, CancellationToken token) =>
 			!ModelState.IsValid ? Invalid() : Answer(await _groupUsersService.RemoveMember(User.GetUserId(), form, token));
 
+		// the group's owner deletes it, with the login's password (R6): its members and followers are told, its name stays
+		// taken (GroupRemoval)
+		[HttpPost, Route("/clientapi/group/delete"), Microsoft.AspNetCore.RateLimiting.EnableRateLimiting(Infrastructure.RateLimiting.Accounts)]
+		public async Task<IActionResult> Delete(DeleteGroupForm form, [FromServices] IRootUsersService users, [FromServices] IGroupRemoval groups,
+			[FromServices] StaticServices.DbEntities dbEntities, CancellationToken token)
+		{
+			if (!ModelState.IsValid)
+				return Invalid();
+			var rootId = User.GetUserId();
+			if (!await users.PasswordMatches(rootId, form.Password))
+				return StatusCode(StatusCodes.Status403Forbidden, new WebResult().Invalidate(_localizer[RootUsersService.NoMatch], StatusCodes.Status403Forbidden));
+			var owns = await dbEntities.RootToAvatars.Match(ra => ra.RootId == rootId && ra.AvatarId == form.AvatarId).ExecuteAnyAsync(token);
+			var group = owns ? await dbEntities.Groups.MatchID(form.GroupId).Match(g => !g.DeletionAt.HasValue).ExecuteFirstAsync(token) : default;
+			if (group == default)
+				return NotFound(new WebResult().Invalidate(_localizer["Group not found."], StatusCodes.Status404NotFound));
+			if (group.OwnerAvatarId != form.AvatarId)
+				return StatusCode(StatusCodes.Status403Forbidden, new WebResult().Invalidate(_localizer["Only the group's owner can delete it."], StatusCodes.Status403Forbidden));
+			await groups.Remove(group.ID, CancellationToken.None);
+			return Ok();
+		}
+
 		IActionResult Invalid() => BadRequest(new WebResult().Invalidate(_localizer["Invalid model."]));
 
 		IActionResult Answer(WebResult result) => result.IsValid ? Ok(result.Data) : StatusCode(result.StatusCode, result);