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/Hubs/GovernanceDashboard.hs

@@ -92,7 +92,7 @@ instance View GovernanceDashboardView where
             </table>
         </div>
     |]
-  where
+      where
     awaitingDecision  = filter (isAwaitingDecision allDecisions) allRequirements
     regressedWidgets  = filter (\w -> w.id `elem` regressionWidgetIds) widgets