Rate limits on accounts and inboxes, a database dump before every deploy

- Sign-up, login, the invitation flows and password recovery allow ten
  requests a minute per client address; the inboxes give each sending
  origin (the keyId's) a bucket of 300 that refills at 300 a minute, and
  answer 429 beyond it, which peers retry.
- deploy.yml dumps the PrivaPub database to /var/backups before it stops
  the service (the last seven are kept), and after the swap checks that
  Swagger answers 404 and that the shared inbox answers junk with 400 and
  an unsigned activity with 401.
- ActivityPubClient and PostBoost, never used, are gone.

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

PrivaPub/Federation/Controllers/PeasantsController.cs

@@ -1,4 +1,5 @@
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.RateLimiting;
 
 using MongoDB.Entities;
 
@@ -11,6 +12,7 @@ using PostEntity = PrivaPub.Models.Post.Post;
 using PrivaPub.Federation.Actors;
 using PrivaPub.Federation.Rendering;
 using PrivaPub.Federation.Inbox;
+using PrivaPub.Infrastructure;
 
 namespace PrivaPub.Federation.Controllers
 {
@@ -113,7 +115,7 @@ namespace PrivaPub.Federation.Controllers
 			return Activity(note);
 		}
 
-		[HttpPost, Route("{actor}/mouth")]
+		[HttpPost, Route("{actor}/mouth"), EnableRateLimiting(RateLimiting.Inbox)]
 		public async Task<IActionResult> Inbox(string actor, CancellationToken token)
 		{
 			var local = await _localActors.FindByUserName(actor, token);
@@ -122,11 +124,11 @@ namespace PrivaPub.Federation.Controllers
 			return Answer(await _inbox.Receive(Request, local, token));
 		}
 
-		[HttpPost, Route("{actor}/human-centipede")]
+		[HttpPost, Route("{actor}/human-centipede"), EnableRateLimiting(RateLimiting.Inbox)]
 		public async Task<IActionResult> ActorSharedInbox(string actor, CancellationToken token) =>
 			Answer(await _inbox.Receive(Request, default, token));
 
-		[HttpPost, Route("/human-centipede")]
+		[HttpPost, Route("/human-centipede"), EnableRateLimiting(RateLimiting.Inbox)]
 		public async Task<IActionResult> SharedInbox(CancellationToken token) =>
 			Answer(await _inbox.Receive(Request, default, token));