Implemented phase 5 for the POC prototype in the Website service.

Services/Website/Tests/Library/Cases/Internal/Components/SiteHeaderTests.swift

@@ -35,13 +35,23 @@ struct SiteHeaderTests {
         #expect(html.contains(#"href="/sell""#))
         #expect(html.contains(">MV<"))
         #expect(html.contains(">Mara<"))
-        #expect(html.contains(#"action="/sign-out" method="post""#))
+        // Signing out lives on the account screen.
+        #expect(!html.contains("/sign-out"))
         #expect(!html.contains(#"href="/sign-in""#))
     }
 
     @Test
-    func `links the shop of a seller alone`() {
-        #expect(!SiteHeader(viewer: .init(displayName: "Mara")).render().contains(#"href="/sell""#))
+    func `leads a seller to their shop, and anyone else to opening one`() {
+        let buyer = SiteHeader(viewer: .init(displayName: "Mara")).render()
+
+        #expect(!buyer.contains(#"href="/sell""#))
+        #expect(buyer.contains(#"href="/sell/open-a-shop""#))
+        #expect(buyer.contains(">Open a shop<"))
+    }
+
+    @Test
+    func `counts one new match in the singular`() {
+        #expect(SiteHeader(viewer: .init(displayName: "Mara", newWantMatches: 1)).render().contains(#"aria-label="Want list, 1 new match""#))
     }
 
     @Test