Implemented phase 2 for the POC prototype in the Website service.

Services/Website/Sources/Library/Internal/Pages/IndexPage.swift

@@ -24,6 +24,9 @@ struct IndexPage {
     /// The public origin the page derives its canonical URL and language alternates from, or `nil` to omit them.
     let siteOrigin: String?
 
+    /// The signed-in viewer, or `nil` when signed out.
+    let viewer: Viewer?
+
     /// Resolves the page's text from the bundled String Catalog for the page's ``locale``.
     private let localize: Localize
 
@@ -36,13 +39,16 @@ struct IndexPage {
     ///   - siteOrigin: the public origin the page derives its canonical URL and language alternates from, or `nil` (the default) to omit them.
     ///   - analytics: the analytics tracker embedded in the document head, or `nil` (the default) to omit it.
     ///   - listings: the listings the page shows in its rows; none by default.
+    ///   - viewer: the signed-in viewer, or `nil` (the default) when signed out.
     init(
         locale: Locale,
         assetVersion: String? = nil,
         siteOrigin: String? = nil,
         analytics: Analytics? = nil,
-        listings: HomeListings = .init()
+        listings: HomeListings = .init(),
+        viewer: Viewer? = nil
     ) {
+        self.viewer = viewer
         self.analytics = analytics
         self.assetVersion = assetVersion
         self.listings = listings
@@ -90,7 +96,7 @@ extension IndexPage: Page {
     // MARK: Properties
 
     var content: some HTML {
-        SiteLayout {
+        SiteLayout(viewer: viewer) {
             div(.class("page home")) {
                 section(.class("hero")) {
                     div(.class("hero__text")) {