Use UrlPathPrefix for agent-skill learn-more link (#2908)

* Fix agent-skill learn-more link to respect UrlPathPrefix

The hardcoded /explore-analyze/ai-features/agent-skills link didn't
resolve in preview environments where the URL path has a prefix.
Now computed from block.Build.UrlPathPrefix like other internal links.

Co-authored-by: Claude <noreply@anthropic.com>
Made-with: Cursor

* Use absolute URL for agent-skill learn-more link

Simpler than UrlPathPrefix computation and works correctly in all
environments (production, preview, local).

Co-authored-by: Claude <noreply@anthropic.com>
Made-with: Cursor

* Use UrlPathPrefix for agent-skill learn-more link

Compute the learn-more URL from block.Build.UrlPathPrefix so it
resolves correctly in all environments (production, preview, local).

Co-authored-by: Claude <noreply@anthropic.com>
Made-with: Cursor

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: theletterf

src/Elastic.Markdown/Myst/Directives/AgentSkill/AgentSkillView.cshtml

@@ -13,7 +13,7 @@
 			{
 				@Model.RenderBlock()
 			}
-			<p><a href="/explore-analyze/ai-features/agent-skills">Learn more about agent skills for Elastic</a></p>
+			<p><a href="@Model.LearnMoreUrl">Learn more about agent skills for Elastic</a></p>
 		</div>
 		<a href="@Model.Url" target="_blank" rel="noopener noreferrer" class="agent-skill-button">
 			Get the skill

src/Elastic.Markdown/Myst/Directives/AgentSkill/AgentSkillViewModel.cs

@@ -8,4 +8,5 @@ public class AgentSkillViewModel : DirectiveViewModel
 {
 	public required string Url { get; init; }
 	public bool HasBody { get; init; }
+	public required string LearnMoreUrl { get; init; }
 }

src/Elastic.Markdown/Myst/Directives/DirectiveHtmlRenderer.cs

@@ -229,11 +229,13 @@ private static void WriteAgentSkill(HtmlRenderer renderer, AgentSkillBlock block
 		if (string.IsNullOrEmpty(block.Url))
 			return;
 
+		var prefix = block.Build.UrlPathPrefix?.TrimEnd('/') ?? string.Empty;
 		var slice = AgentSkillView.Create(new AgentSkillViewModel
 		{
 			DirectiveBlock = block,
 			Url = block.Url,
-			HasBody = block.Count > 0
+			HasBody = block.Count > 0,
+			LearnMoreUrl = $"{prefix}/explore-analyze/ai-features/agent-skills"
 		});
 		RenderRazorSlice(slice, renderer);
 	}