Implemented phase 1 for the POC prototype in the Website service.

Services/Website/Sources/Library/Public/Controllers/RootController.swift

@@ -31,10 +31,12 @@ public struct RootController<Context: RequestContext> {
     ///   - assetVersion: the version token appended to the page's asset URLs, or `nil` (the default) to leave them unversioned.
     ///   - 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 the landing page embeds, or `nil` (the default) to omit it.
+    ///   - listings: the listings the landing page shows in its rows; none by default.
     public init(
         assetVersion: String? = nil,
         siteOrigin: String? = nil,
-        analytics: Analytics? = nil
+        analytics: Analytics? = nil,
+        listings: HomeListings = .init()
     ) {
         self.negotiate = .init(bundle: .module)
         // The bare route negotiates, so the pages declare `Vary: Accept-Language`; the prefixed editions share the cache
@@ -47,7 +49,8 @@ public struct RootController<Context: RequestContext> {
                 locale: $0,
                 assetVersion: assetVersion,
                 siteOrigin: siteOrigin,
-                analytics: analytics
+                analytics: analytics,
+                listings: listings
             )
         }
     }