An event card joins and leaves the event

PrivaPub lets a persona join another server's event (owner decision
2026-10-05). The card of a remote event shows the persona's participation
(pending, accepted, rejected) with Join or Leave, except for events by
invitation or taken on another site. Joining is public on the event's
server, so the first join asks the persona once, as reactions and votes do,
remembered apart from them (PublicAct).

The e2e joins the event SocialPub's Mobilizon scenario keeps, checks the
participant on Mobilizon and PrivaPub's answer, and leaves it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LsXgEaXee4GCU1hwYgPJXw

tests/e2e/Actions/VoteAndReactTests.cs

@@ -47,7 +47,7 @@ namespace decePubClient.E2E.Actions
 		}
 
 		// the one-time notice, when this persona has not seen it yet
-		static async Task AcceptNoticeIfAsked(IPage page)
+		internal static async Task AcceptNoticeIfAsked(IPage page)
 		{
 			var proceed = page.GetByRole(AriaRole.Button, new() { Name = "Continue" });
 			try