One visibility rule for every public read

VisibilityPolicy.IsPublic is the single expression for "anyone may see
this" (Public or Unlisted, not deleted); the outbox, the object and
activity endpoints, the HTML pages and NodeInfo all use it instead of
spelling it out. CanSee answers for a persona: the author, a mentioned
local persona, a conversation member for Direct, a circle member for
Circle; followers-only waits for P1.2's follows.

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

PrivaPub/Web/Pages/Pages.cs

@@ -3,6 +3,7 @@ using Microsoft.AspNetCore.Mvc.RazorPages;
 
 using MongoDB.Entities;
 
+using PrivaPub.Domain.Privacy;
 using PrivaPub.Federation.Actors;
 using PrivaPub.Federation.Rendering;
 using PrivaPub.Models.Federation;
@@ -70,7 +71,7 @@ namespace PrivaPub.Web.Pages
 			var posts = await (Actor.Kind == LocalActorKind.Group
 					? _dbEntities.Posts.Match(p => p.GroupId == Actor.Id)
 					: _dbEntities.Posts.Match(p => p.GroupUserId == Actor.Id && !p.IsFederatedCopy))
-				.Match(p => !p.DeletedAt.HasValue && (p.Visibility == PostVisibility.Public || p.Visibility == PostVisibility.Unlisted))
+				.Match(VisibilityPolicy.IsPublic)
 				.Sort(p => p.ID, Order.Descending)
 				.Limit(PageSize)
 				.ExecuteAsync(token);
@@ -111,8 +112,8 @@ namespace PrivaPub.Web.Pages
 			if (Actor is not { IsFederated: true, Kind: LocalActorKind.Person })
 				return NotFound();
 			var post = await _dbEntities.Posts
-				.Match(p => p.ID == id && p.GroupUserId == Actor.Id && !p.IsFederatedCopy && !p.DeletedAt.HasValue
-					&& (p.Visibility == PostVisibility.Public || p.Visibility == PostVisibility.Unlisted))
+				.Match(p => p.ID == id && p.GroupUserId == Actor.Id && !p.IsFederatedCopy)
+				.Match(VisibilityPolicy.IsPublic)
 				.ExecuteFirstAsync(token);
 			if (post == default)
 				return NotFound();