fix(WP-0017/E3): Layer 3 error fixes — controllers and views

Fix compilation errors across 6 controllers and 29 views: import cleanup,
ResponseException pattern for API auth, type fixes, unused import removal.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Web/View/InteractionReportingContracts/Show.hs

@@ -57,12 +57,12 @@ instance View ShowView where
             <pre class="text-xs text-blue-900 overflow-auto">curl -X POST {contract.endpointPath} \
   -H "Authorization: Bearer &lt;hub-api-key&gt;" \
   -H "Content-Type: application/json" \
-  -d '{"{"}
+  -d '&#123;
     "widget_id": "&lt;uuid&gt;",
     "hub_id": "&lt;uuid&gt;",
     "event_type": "clicked",
     "occurred_at": "2026-03-29T12:00:00Z"
-{"}"}'</pre>
+&#125;'</pre>
         </div>
 
         <div class="mt-4 text-xs text-gray-400">