test(02-01): add failing test for the presentations prefix

- /_presentations must be a plain 404, not the SPA shell
- A router without the presentations plugin has no public document route

plugin_test.go

@@ -165,6 +165,11 @@ func TestRoutes(t *testing.T) {
 	if !slices.Equal(got, want) {
 		t.Errorf("routes =\n%v\nwant\n%v", got, want)
 	}
+	for _, rt := range router.Routes() {
+		if rt.Pattern == "/prezentacje/{slugHash}" {
+			t.Errorf("GET /prezentacje/{slugHash} is registered without golem15.presentations")
+		}
+	}
 }
 
 func TestAdminCompiles(t *testing.T) {