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/HubCapabilityManifests/Edit.hs

@@ -59,7 +59,7 @@ instance View EditView where
                 <div class="flex gap-3">
                     <button type="submit"
                             class="bg-indigo-600 text-white text-sm px-4 py-2 rounded hover:bg-indigo-700"
-                            {if manifest.status /= "draft" then ("disabled" :: Text) else ""}>
+                            disabled={manifest.status /= "draft"}>
                         Save
                     </button>
                     {if manifest.status == "draft" then renderActivateLink manifest.id else mempty}