feat(admin): open controller-link settings entries from the settings index

A settings entry with a controller opens that controller's route from
its card (settingsPath); singleton cards still open /settings/<code>.
On a linked controller with no navigation entry of its own the rail
marks Settings current, the breadcrumbs read Settings > entry label
(plus the record title on record and create routes) and the page title
uses the entry label. The settings docs describe the admin behaviour;
the embedded admin shell is rebuilt.

modules/boardwalk/dist/index.html

@@ -7,7 +7,7 @@
     <meta name="summer-admin-base" content="__SUMMER_ADMIN_BASE__" />
     <link rel="icon" href="./favicon.ico" sizes="48x48" />
     <title>SummerCMS</title>
-    <script type="module" crossorigin src="./assets/index-kMerM-BR.js"></script>
+    <script type="module" crossorigin src="./assets/index-BK2Ktgov.js"></script>
     <link rel="stylesheet" crossorigin href="./assets/index-BhDUy2Lr.css">
   </head>
   <body>