Generate navigation and render page embeds from PocketBase

Elternbeirat.Web/Features/Layout/NavBuilder.cs

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+using Elternbeirat.Contracts;
+
+namespace Elternbeirat.Web.Features.Layout;
+
+/// <summary>
+/// Builds the header and footer navigation from the public pages. Pages carry a
+/// <see cref="Page.Location"/> ("header"/"footer"/"") and an <see cref="Page.Order"/>;
+/// pages without a location are sub-pages and never appear in a menu.
+/// </summary>
+public static class NavBuilder
+{
+    /// <summary>Header links, ordered, built from pages with location "header".</summary>
+    public static IReadOnlyList<NavLinkItem> Header(IReadOnlyList<Page> pages) =>
+        Build(pages, "header");
+
+    /// <summary>Footer links, ordered, built from pages with location "footer".</summary>
+    public static IReadOnlyList<NavLinkItem> Footer(IReadOnlyList<Page> pages) =>
+        Build(pages, "footer");
+
+    private static List<NavLinkItem> Build(IReadOnlyList<Page> pages, string location) =>
+        [.. pages
+            .Where(page => string.Equals(page.Location, location, StringComparison.Ordinal))
+            .OrderBy(page => page.Order)
+            .Select(page => new NavLinkItem(HrefFor(page.Slug), page.Title))];
+
+    // The home page owns "/" (served by the Home component); every other slug is
+    // reached at "/{slug}", where either a literal route or the catch-all content
+    // page renders it.
+    private static string HrefFor(string slug) =>
+        string.Equals(slug, "home", StringComparison.Ordinal) ? "/" : $"/{slug}";
+}