Pinned posts on profiles, and pinning from the card

A profile shows the posts the account pins above its posts (pinned=true: for an account elsewhere, what it features,
which PrivaPub now keeps); the persona pins and unpins its own public and unlisted posts from the card's menu, and
PrivaPub tells its followers. tests/e2e/Actions/PinTests.cs pins from the card and finds the post first on the profile;
the whole e2e suite passes against the reseeded village (122, 4 skipped).

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

Components/Content.razor

@@ -293,6 +293,14 @@
 										}
 										else
 										{
+											@if (CanPin(status))
+											{
+												<DButton Size="DSize.Sm" class="justify-start whitespace-nowrap" Disabled="IsDefaultDisabled || isActing"
+														 OnClick="() => Act(status.Pinned ? StatusAction.Unpin : StatusAction.Pin)" data-pin>
+													<i aria-hidden="true" class="ion-md-pin text-base"></i>
+													<span>@(status.Pinned ? Localizer["Unpin from profile"] : Localizer["Pin on profile"])</span>
+												</DButton>
+											}
 											<DButton Size="DSize.Sm" class="justify-start whitespace-nowrap" Disabled="IsDefaultDisabled" OnClick="ToggleEdit" data-edit>
 												<i aria-hidden="true" class="ion-md-create text-base"></i>
 												<span>@Localizer["Edit"]</span>
@@ -701,6 +709,8 @@
 
 	HashSet<int> pollChoices = [];
 
+	// a profile shows the persona's own public and unlisted posts it pins, as Mastodon allows
+	bool CanPin(Status status) => !Compact && !Post.Located && status.Reblog is null && status.Visibility is ("public" or "unlisted");
 	bool CanVote(Poll poll) => !poll.Expired && poll.Voted != true && !IsOwn && !Compact && !Post.Located;
 
 	void ToggleChoice(Poll poll, int index)