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/StaticPages/Landing.hs

@@ -115,9 +115,9 @@ instance View LandingView where
         </div>
     |]
       where
-        chainLink label color = [hsx|
+        chainLink (label :: Text) (color :: Text) = [hsx|
             <span class={"inline-block px-2 py-1 rounded text-xs bg-" <> color <> "-100 text-" <> color <> "-800 font-mono"}>
-                {label :: Text}
+                {label}
             </span>
         |]
         arrow = [hsx|<span class="text-gray-400">→</span>|]