Add validation and title as mandatory

Author: theletterf

src/Elastic.Documentation.Configuration/Builder/TableOfContentsConfiguration.cs

@@ -156,6 +156,22 @@ private IReadOnlyCollection<ITocItem> ReadChildren(YamlStreamReader reader, KeyV
 				case "crosslink":
 					hiddenFile = false;
 					crossLink = reader.ReadString(entry);
+					// Validate crosslink URI early
+					if (string.IsNullOrWhiteSpace(crossLink))
+					{
+						reader.EmitError("Cross-link entries must specify a non-empty 'crosslink' URI", tocEntry);
+						crossLink = null; // Reset to prevent further processing
+					}
+					else if (!Uri.TryCreate(crossLink, UriKind.Absolute, out var parsedUri))
+					{
+						reader.EmitError($"Cross-link URI '{crossLink}' is not a valid absolute URI format", tocEntry);
+						crossLink = null; // Reset to prevent further processing
+					}
+					else if (parsedUri.Scheme is "http" or "https" or "ftp" or "file")
+					{
+						reader.EmitError($"Cross-link URI '{crossLink}' cannot use standard web schemes (http, https, ftp, file). Use cross-repository schemes like 'docs-content://', 'kibana://', etc.", tocEntry);
+						crossLink = null; // Reset to prevent further processing
+					}
 					break;
 				case "folder":
 					folder = ReadFolder(reader, entry, parentPath);
@@ -174,6 +190,13 @@ private IReadOnlyCollection<ITocItem> ReadChildren(YamlStreamReader reader, KeyV
 			}
 		}
 
+		// Validate that crosslink entries have titles
+		if (crossLink is not null && string.IsNullOrWhiteSpace(title))
+		{
+			reader.EmitError($"Cross-link entries must have a 'title' specified. Cross-link: {crossLink}", tocEntry);
+			return null;
+		}
+
 		if (toc is not null)
 		{
 			foreach (var f in toc.Files)

src/Elastic.Markdown/IO/Navigation/CrossLinkNavigationItem.cs

@@ -13,44 +13,15 @@ public record CrossLinkNavigationItem : ILeafNavigationItem<INavigationModel>
 {
 	// Override Url accessor to use ResolvedUrl if available
 	string INavigationItem.Url => ResolvedUrl ?? Url;
-	public CrossLinkNavigationItem(string url, string? title, DocumentationGroup group, bool hidden = false)
+	public CrossLinkNavigationItem(string url, string title, DocumentationGroup group, bool hidden = false)
 	{
 		_url = url;
-		NavigationTitle = title ?? GetNavigationTitleFromUrl(url);
+		NavigationTitle = title;
 		Parent = group;
 		NavigationRoot = group.NavigationRoot;
 		Hidden = hidden;
 	}
 
-	private string GetNavigationTitleFromUrl(string url)
-	{
-		// Extract a decent title from the URL
-		try
-		{
-			if (Uri.TryCreate(url, UriKind.Absolute, out var uri))
-			{
-				// Get the last segment of the path and remove extension
-				var lastSegment = uri.AbsolutePath.Split('/').Last();
-				lastSegment = Path.GetFileNameWithoutExtension(lastSegment);
-
-				// Convert to title case (simple version)
-				if (!string.IsNullOrEmpty(lastSegment))
-				{
-					var words = lastSegment.Replace('-', ' ').Replace('_', ' ').Split(' ');
-					var titleCase = string.Join(" ", words.Select(w =>
-						string.IsNullOrEmpty(w) ? "" : char.ToUpper(w[0]) + w[1..].ToLowerInvariant()));
-					return titleCase;
-				}
-			}
-		}
-		catch
-		{
-			// Fall back to URL if parsing fails
-		}
-
-		return url;
-	}
-
 	public INodeNavigationItem<INavigationModel, INavigationItem>? Parent { get; set; }
 	public IRootNavigationItem<INavigationModel, INavigationItem> NavigationRoot { get; }
 	// Original URL from the cross-link

src/Elastic.Markdown/IO/Navigation/DocumentationGroup.cs

@@ -123,12 +123,30 @@ void AddToNavigationItems(INavigationItem item, ref int fileIndex)
 		{
 			if (tocItem is CrossLinkReference crossLink)
 			{
+				// Validate that cross-link URI is not empty
+				if (string.IsNullOrWhiteSpace(crossLink.CrossLinkUri))
+				{
+					context.EmitError(context.ConfigurationPath,
+						"Cross-link entries must have a 'crosslink' URI specified.");
+					continue;
+				}
+
+				// Validate that cross-link URI is a valid URI format
+				if (!Uri.TryCreate(crossLink.CrossLinkUri, UriKind.Absolute, out var parsedUri))
+				{
+					context.EmitError(context.ConfigurationPath,
+						$"Cross-link URI '{crossLink.CrossLinkUri}' is not a valid absolute URI format.");
+					continue;
+				}
+
+				// Validate that cross-link has a title
 				if (string.IsNullOrWhiteSpace(crossLink.Title))
 				{
 					context.EmitError(context.ConfigurationPath,
 						$"Cross-link entries must have a 'title' specified. Cross-link: {crossLink.CrossLinkUri}");
 					continue;
 				}
+
 				// Create a special navigation item for cross-repository links
 				var crossLinkItem = new CrossLinkNavigationItem(crossLink.CrossLinkUri, crossLink.Title, this, crossLink.Hidden);
 				AddToNavigationItems(crossLinkItem, ref fileIndex);