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/Infrastructure/Data/Migrations/_020_silenced_servers_limit_their_posts.cs

@@ -0,0 +1,13 @@
+using MongoDB.Entities;
+
+namespace PrivaPub.Infrastructure.Data.Migrations
+{
+	// Posts carry their author's moderation since completion program R6 (Post.AuthorLimited, AuthorSuspended): the posts
+	// already held from servers silenced before then are limited, as those arriving from now on are, and any account
+	// already silenced or suspended gets the same (Domain/Moderation/ModerationFlags.cs, which a restore runs too)
+	public class _020_silenced_servers_limit_their_posts : IMigration
+	{
+		public async Task UpgradeAsync() =>
+			await Domain.Moderation.ModerationFlags.Recompute(DB.Default.Database(), CancellationToken.None);
+	}
+}