P6 done: personas can be quoted, under the owner's default of anyone, automatically

- Our public and unlisted posts state interactionPolicy.canQuote. The policy comes from the post, then the persona
  (`source[quote_policy]`: public, followers or nobody; default public as the owner chose), and is always nobody for
  followers-only posts and DMs.
- QuoteRequests are answered with Accept{result} naming a parrot-licence at /peasants/{name}/parrot-licences/{id}
  (the route name the owner chose), or with Reject. Followers-only checks that the requester really follows.
- A licence is a QuoteAuthorization naming both posts; revoking it (POST /api/v1/statuses/:id/quotes/:quoting_id/revoke)
  marks it 410, sends Delete{licence} to the quoter and the persona's followers, and revokes our own copy of the quote.
- A quote that arrives with one of our licences is accepted only if that licence is ours, unrevoked and names exactly
  that quoting post. One persona quoting another gets a licence too.
- Mastodon API: quote_approval for our posts (automatic, followers, current_user), `quote_approval_policy` when posting,
  PUT /api/v1/statuses/:id/interaction_policy, `source.quote_policy`.

Checked live: GoToSocial still accepts our posts with the policy stated, and leaves likes, replies and boosts open.

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

PrivaPub/Api/Mastodon/Controllers/AccountsController.cs

@@ -79,6 +79,8 @@ namespace PrivaPub.Api.Mastodon.Controllers
 				avatar.Settings.DefaultSensitive = sensitive;
 			if (Params.Has("source[language]"))
 				avatar.Settings.DefaultLanguage = Params.Get("source[language]");
+			if (Params.Get("source[quote_policy]") is { } quotePolicy && QuotePolicies.IsKnown(quotePolicy))
+				avatar.Settings.QuotePolicy = quotePolicy;
 			var fields = new Dictionary<string, string>();
 			for (var i = 0; i < 4; i++)
 			{

PrivaPub/Api/Mastodon/Controllers/StatusesController.cs

@@ -9,6 +9,9 @@ using PrivaPub.Api.Mastodon.Mappers;
 using PrivaPub.Domain.Privacy;
 using PrivaPub.Domain.Statuses;
 using PrivaPub.Models.Post;
+using PrivaPub.Models.User;
+using PrivaPub.Federation.Rendering;
+using PrivaPub.Federation.Outbox;
 using PrivaPub.StaticServices;
 
 using PostEntity = PrivaPub.Models.Post.Post;
@@ -24,9 +27,14 @@ namespace PrivaPub.Api.Mastodon.Controllers
 		readonly MastodonMapper _mapper;
 		readonly DbEntities _dbEntities;
 		readonly IMemoryCache _cache;
+		readonly IQuoteService _quotes;
+		readonly IOutboxPublisher _outbox;
 
-		public StatusesController(IStatusService statuses, MastodonMapper mapper, DbEntities dbEntities, IMemoryCache cache)
+		public StatusesController(IStatusService statuses, MastodonMapper mapper, DbEntities dbEntities, IMemoryCache cache, IQuoteService quotes,
+			IOutboxPublisher outbox)
 		{
+			_quotes = quotes;
+			_outbox = outbox;
 			_statuses = statuses;
 			_mapper = mapper;
 			_dbEntities = dbEntities;
@@ -55,6 +63,7 @@ namespace PrivaPub.Api.Mastodon.Controllers
 				Language = Params.Get("language") ?? Me.Settings.DefaultLanguage,
 				MediaIds = Params.List("media_ids"),
 				QuotedStatusId = Params.Get("quoted_status_id"),
+				QuotePolicy = Params.Get("quote_approval_policy"),
 				Poll = Params.Has("poll[options]")
 					? new PollDraft(Params.List("poll[options]"), Params.Int("poll[expires_in]") ?? 0, Params.Bool("poll[multiple]") == true,
 						Params.Bool("poll[hide_totals]") == true)
@@ -242,6 +251,32 @@ namespace PrivaPub.Api.Mastodon.Controllers
 			return Json(await _mapper.Statuses(visible, MyId, token));
 		}
 
+		[HttpPost("/api/v1/statuses/{id}/quotes/{quotingId}/revoke"), Scope("write:statuses")]
+		public async Task<IActionResult> RevokeQuote(string id, string quotingId, CancellationToken token)
+		{
+			var quoted = await _dbEntities.Posts.Match(p => p.ID == id && p.GroupUserId == MyId && !p.IsFederatedCopy && !p.DeletedAt.HasValue).ExecuteFirstAsync(token);
+			var quoting = quoted == default ? default : await _dbEntities.Posts.Match(p => p.ID == quotingId && p.QuotedPostId == quoted.ID).ExecuteFirstAsync(token);
+			if (quoting == default || !await _quotes.RevokeLicence(quoted, quoting, token))
+				return NotFoundError();
+			return Json(await _mapper.Status(await _dbEntities.Posts.MatchID(quoting.ID).ExecuteFirstAsync(token), MyId, token));
+		}
+
+		[HttpPut("/api/v1/statuses/{id}/interaction_policy"), Scope("write:statuses")]
+		public async Task<IActionResult> InteractionPolicy(string id, CancellationToken token)
+		{
+			var post = await _dbEntities.Posts.Match(p => p.ID == id && p.GroupUserId == MyId && !p.IsFederatedCopy && !p.DeletedAt.HasValue).ExecuteFirstAsync(token);
+			if (post == default)
+				return NotFoundError();
+			var policy = Params.Get("quote_approval_policy");
+			if (!QuotePolicies.IsKnown(policy))
+				return Error(StatusCodes.Status422UnprocessableEntity, "Validation failed: Unknown quote approval policy");
+			await DB.Default.Update<PostEntity>().MatchID(post.ID).Modify(p => p.LocalQuotePolicy, policy).ExecuteAsync(token);
+			post.LocalQuotePolicy = policy;
+			if (!post.IsLocalOnly)
+				await _outbox.Publish(Me, post, ActivityPubRenderer.UpdateOf(post, Me, $"policy-{DateTime.UtcNow.Ticks}"), token);
+			return Json(await _mapper.Status(post, MyId, token));
+		}
+
 		[HttpPost("/api/v1/statuses/{id}/bookmark"), Scope("write:bookmarks")]
 		public async Task<IActionResult> Bookmark(string id, CancellationToken token)
 		{