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

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

@@ -30,6 +30,9 @@ struct SearchPage {
     /// The number of shops the matching listings come from.
     let shopCount: Int
 
+    /// The signed-in viewer, or `nil` when signed out.
+    let viewer: Viewer?
+
     // MARK: Initializers
 
     /// Creates the search results screen for a search and the listings matching it.
@@ -37,15 +40,18 @@ struct SearchPage {
     ///   - parameters: the search the screen answers.
     ///   - matches: every listing matching the search; the screen shows the page the parameters ask for.
     ///   - publishers: every publisher a listing can be filtered by.
+    ///   - viewer: the signed-in viewer, or `nil` (the default) when signed out.
     ///   - assetVersion: the version token appended to the page's asset URLs, or `nil` (the default) to leave them unversioned.
     ///   - analytics: the analytics tracker embedded in the document head, or `nil` (the default) to omit it.
     init(
         parameters: SearchParameters,
         matches: [Listing],
         publishers: [String],
+        viewer: Viewer? = nil,
         assetVersion: String? = nil,
         analytics: Analytics? = nil
     ) {
+        self.viewer = viewer
         let slice = Pagination.slice(
             matches,
             page: parameters.page,
@@ -82,7 +88,8 @@ extension SearchPage: Page {
     var content: some HTML {
         SiteLayout(
             active: formats.count == 1 ? formats.first : nil,
-            query: parameters.value(.query)
+            query: parameters.value(.query),
+            viewer: viewer
         ) {
             div(.class("page search")) {
                 div(.class("search__head")) {